fix(funcspec): update meta variable replacement in SQL query

* Implement Scan method for BunInsertQuery, GormInsertQuery, and PgSQLInsertQuery
* Update mock implementations to support Scan method
* Introduce GetForeignKeyColumn utility for foreign key resolution
* Add tests for GetForeignKeyColumn functionality

pkg/common/adapters/database/bun.go

@@ -487,6 +487,14 @@ func normalizeTableAlias(query, expectedAlias, tableName string) string {
 	return modified
 }
 
+func isJoinKeyword(word string) bool {
+	switch strings.ToUpper(word) {
+	case "JOIN", "INNER", "LEFT", "RIGHT", "FULL", "OUTER", "CROSS":
+		return true
+	}
+	return false
+}
+
 func (b *BunSelectQuery) WhereOr(query string, args ...interface{}) common.SelectQuery {
 	b.query = b.query.WhereOr(query, args...)
 	return b
@@ -517,7 +525,7 @@ func (b *BunSelectQuery) Join(query string, args ...interface{}) common.SelectQu
 	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
 		// If query doesn't already have AS, check if it's a simple table name
 		parts := strings.Fields(query)
-		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+		if len(parts) > 0 && !isJoinKeyword(parts[0]) {
 			// Simple table name, add prefix: "table AS prefix"
 			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
 			if len(parts) > 1 {
@@ -552,7 +560,7 @@ func (b *BunSelectQuery) LeftJoin(query string, args ...interface{}) common.Sele
 	joinClause := query
 	if prefix != "" && !strings.Contains(strings.ToUpper(query), " AS ") {
 		parts := strings.Fields(query)
-		if len(parts) > 0 && !strings.HasPrefix(strings.ToUpper(parts[0]), "LEFT") && !strings.HasPrefix(strings.ToUpper(parts[0]), "JOIN") {
+		if len(parts) > 0 && !isJoinKeyword(parts[0]) {
 			joinClause = fmt.Sprintf("%s AS %s", parts[0], prefix)
 			if len(parts) > 1 {
 				joinClause += " " + strings.Join(parts[1:], " ")
@@ -1443,6 +1451,18 @@ func (b *BunInsertQuery) Returning(columns ...string) common.InsertQuery {
 	return b
 }
 
+func (b *BunInsertQuery) prepareValues() {
+	if len(b.values) > 0 {
+		if !b.hasModel {
+			b.query = b.query.Model(&b.values)
+		} else {
+			for k, v := range b.values {
+				b.query = b.query.Value(k, "?", v)
+			}
+		}
+	}
+}
+
 func (b *BunInsertQuery) Exec(ctx context.Context) (res common.Result, err error) {
 	defer func() {
 		if r := recover(); r != nil {
@@ -1450,23 +1470,25 @@ func (b *BunInsertQuery) Exec(ctx context.Context) (res common.Result, err error
 		}
 	}()
 	startedAt := time.Now()
-	if len(b.values) > 0 {
+	b.prepareValues()
-		if !b.hasModel {
-			// If no model was set, use the values map as the model
-			// Bun can insert map[string]interface{} directly
-			b.query = b.query.Model(&b.values)
-		} else {
-			// If model was set, use Value() to add individual values
-			for k, v := range b.values {
-				b.query = b.query.Value(k, "?", v)
-			}
-		}
-	}
 	result, err := b.query.Exec(ctx)
 	recordQueryMetrics(b.metricsEnabled, "INSERT", b.schema, b.entity, b.tableName, startedAt, err)
 	return &BunResult{result: result}, err
 }
 
+func (b *BunInsertQuery) Scan(ctx context.Context, dest interface{}) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = logger.HandlePanic("BunInsertQuery.Scan", r)
+		}
+	}()
+	startedAt := time.Now()
+	b.prepareValues()
+	err = b.query.Scan(ctx, dest)
+	recordQueryMetrics(b.metricsEnabled, "INSERT", b.schema, b.entity, b.tableName, startedAt, err)
+	return err
+}
+
 // BunUpdateQuery implements UpdateQuery for Bun
 type BunUpdateQuery struct {
 	query          *bun.UpdateQuery
@@ -1529,7 +1551,7 @@ func (b *BunUpdateQuery) SetMap(values map[string]interface{}) common.UpdateQuer
 			// Skip primary key updates
 			continue
 		}
-		b.query = b.query.Set(column+" = ?", value)
+		b.query = b.query.Set(column+" = ?", common.ConvertSliceForBun(value))
 	}
 	return b
 }

pkg/common/adapters/database/gorm.go

@@ -3,11 +3,13 @@ package database
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"strings"
 	"sync"
 	"time"
 
 	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
 
 	"github.com/bitechdev/ResolveSpec/pkg/common"
 	"github.com/bitechdev/ResolveSpec/pkg/logger"
@@ -676,15 +678,16 @@ func (g *GormSelectQuery) Exists(ctx context.Context) (exists bool, err error) {
 
 // GormInsertQuery implements InsertQuery for GORM
 type GormInsertQuery struct {
-	db             *gorm.DB
+	db               *gorm.DB
-	reconnect      func(...*gorm.DB) error
+	reconnect        func(...*gorm.DB) error
-	model          interface{}
+	model            interface{}
-	values         map[string]interface{}
+	values           map[string]interface{}
-	schema         string
+	schema           string
-	tableName      string
+	tableName        string
-	entity         string
+	entity           string
-	driverName     string
+	driverName       string
-	metricsEnabled bool
+	metricsEnabled   bool
+	returningColumns []string
 }
 
 func (g *GormInsertQuery) Model(model interface{}) common.InsertQuery {
@@ -718,7 +721,7 @@ func (g *GormInsertQuery) OnConflict(action string) common.InsertQuery {
 }
 
 func (g *GormInsertQuery) Returning(columns ...string) common.InsertQuery {
-	// GORM doesn't have explicit RETURNING, but updates the model
+	g.returningColumns = columns
 	return g
 }
 
@@ -749,6 +752,76 @@ func (g *GormInsertQuery) Exec(ctx context.Context) (res common.Result, err erro
 	return &GormResult{result: result}, result.Error
 }
 
+func (g *GormInsertQuery) Scan(ctx context.Context, dest interface{}) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			err = logger.HandlePanic("GormInsertQuery.Scan", r)
+		}
+	}()
+	startedAt := time.Now()
+
+	var returningCols []clause.Column
+	for _, col := range g.returningColumns {
+		returningCols = append(returningCols, clause.Column{Name: col})
+	}
+
+	db := g.db.WithContext(ctx)
+	if len(returningCols) > 0 {
+		db = db.Clauses(clause.Returning{Columns: returningCols})
+	}
+
+	var result *gorm.DB
+	switch {
+	case g.model != nil:
+		result = db.Create(g.model)
+	case g.values != nil:
+		result = db.Create(g.values)
+	default:
+		result = db.Create(map[string]interface{}{})
+	}
+
+	if isDBClosed(result.Error) && g.reconnect != nil {
+		if reconnErr := g.reconnect(g.db); reconnErr == nil {
+			result = db.Create(g.model)
+		}
+	}
+
+	recordQueryMetrics(g.metricsEnabled, "INSERT", g.schema, g.entity, g.tableName, startedAt, result.Error)
+	if result.Error != nil {
+		return result.Error
+	}
+
+	// Extract the returning column value from the model or values map
+	if len(g.returningColumns) == 1 {
+		col := g.returningColumns[0]
+		if g.model != nil {
+			val := reflect.ValueOf(g.model)
+			if val.Kind() == reflect.Ptr {
+				val = val.Elem()
+			}
+			if val.Kind() == reflect.Struct {
+				for i := 0; i < val.NumField(); i++ {
+					f := val.Type().Field(i)
+					dbTag := strings.Split(f.Tag.Get("bun"), ",")[0]
+					jsonTag := strings.Split(f.Tag.Get("json"), ",")[0]
+					if strings.EqualFold(f.Name, col) || dbTag == col || jsonTag == col {
+						reflect.ValueOf(dest).Elem().Set(val.Field(i))
+						return nil
+					}
+				}
+			}
+		}
+		if g.values != nil {
+			if v, ok := g.values[col]; ok {
+				reflect.ValueOf(dest).Elem().Set(reflect.ValueOf(v))
+				return nil
+			}
+		}
+	}
+
+	return nil
+}
+
 // GormUpdateQuery implements UpdateQuery for GORM
 type GormUpdateQuery struct {
 	db             *gorm.DB

pkg/common/adapters/database/pgsql.go

@@ -708,6 +708,51 @@ func (p *PgSQLInsertQuery) Exec(ctx context.Context) (res common.Result, err err
 	return &PgSQLResult{result: result}, nil
 }
 
+func (p *PgSQLInsertQuery) Scan(ctx context.Context, dest interface{}) (err error) {
+	startedAt := time.Now()
+	defer func() {
+		if r := recover(); r != nil {
+			err = logger.HandlePanic("PgSQLInsertQuery.Scan", r)
+		}
+		recordQueryMetrics(p.metricsEnabled, "INSERT", p.schema, p.entity, p.tableName, startedAt, err)
+	}()
+
+	if len(p.values) == 0 {
+		return fmt.Errorf("no values to insert")
+	}
+
+	columns := make([]string, 0, len(p.values))
+	placeholders := make([]string, 0, len(p.values))
+	args := make([]interface{}, 0, len(p.values))
+	i := 1
+	for _, col := range p.valueOrder {
+		columns = append(columns, col)
+		placeholders = append(placeholders, fmt.Sprintf("$%d", i))
+		args = append(args, p.values[col])
+		i++
+	}
+
+	query := fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s)",
+		p.tableName,
+		strings.Join(columns, ", "),
+		strings.Join(placeholders, ", "))
+
+	if len(p.returning) > 0 {
+		query += " RETURNING " + strings.Join(p.returning, ", ")
+	}
+
+	logger.Debug("PgSQL INSERT (Scan): %s [args: %v]", query, args)
+
+	var row *sql.Row
+	if p.tx != nil {
+		row = p.tx.QueryRowContext(ctx, query, args...)
+	} else {
+		row = p.db.QueryRowContext(ctx, query, args...)
+	}
+
+	return row.Scan(dest)
+}
+
 // PgSQLUpdateQuery implements UpdateQuery for PostgreSQL
 type PgSQLUpdateQuery struct {
 	db             *sql.DB

pkg/common/handler_utils.go

@@ -3,6 +3,7 @@ package common
 import (
 	"fmt"
 	"reflect"
+	"strconv"
 	"strings"
 
 	"github.com/bitechdev/ResolveSpec/pkg/logger"
@@ -261,3 +262,48 @@ func GetTableNameFromModel(model interface{}) string {
 	// This handles cases like "MasterTaskItem" -> "mastertaskitem"
 	return strings.ToLower(modelType.Name())
 }
+
+// ConvertSliceForBun converts []interface{} values to PostgreSQL array literal strings.
+// BUN's fallback appender for []interface{} is JSON encoding, which produces "[]" —
+// invalid PostgreSQL array syntax. PostgreSQL expects "{}" for empty arrays and
+// "{elem1,elem2}" for non-empty ones. All other value types are returned unchanged.
+func ConvertSliceForBun(value interface{}) interface{} {
+	arr, ok := value.([]interface{})
+	if !ok {
+		return value
+	}
+	if len(arr) == 0 {
+		return "{}"
+	}
+	parts := make([]string, len(arr))
+	for i, elem := range arr {
+		switch e := elem.(type) {
+		case string:
+			needsQuote := e == "" || strings.ContainsAny(e, `,"\\{}`+"\t\n\r ")
+			if needsQuote {
+				e = strings.ReplaceAll(e, `\`, `\\`)
+				e = strings.ReplaceAll(e, `"`, `""`)
+				parts[i] = `"` + e + `"`
+			} else {
+				parts[i] = e
+			}
+		case float64:
+			if e == float64(int64(e)) {
+				parts[i] = strconv.FormatInt(int64(e), 10)
+			} else {
+				parts[i] = strconv.FormatFloat(e, 'f', -1, 64)
+			}
+		case bool:
+			if e {
+				parts[i] = "t"
+			} else {
+				parts[i] = "f"
+			}
+		case nil:
+			parts[i] = "NULL"
+		default:
+			parts[i] = fmt.Sprintf("%v", e)
+		}
+	}
+	return "{" + strings.Join(parts, ",") + "}"
+}

pkg/common/handler_utils_test.go

@@ -106,3 +106,66 @@ func TestExtractTagValue(t *testing.T) {
 		})
 	}
 }
+
+func TestConvertSliceForBun(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    interface{}
+		expected interface{}
+	}{
+		{
+			name:     "empty slice produces empty pg array",
+			input:    []interface{}{},
+			expected: "{}",
+		},
+		{
+			name:     "string elements",
+			input:    []interface{}{"a", "b", "c"},
+			expected: "{a,b,c}",
+		},
+		{
+			name:     "string element needing quotes",
+			input:    []interface{}{"hello world", "ok"},
+			expected: `{"hello world",ok}`,
+		},
+		{
+			name:     "string with comma",
+			input:    []interface{}{"a,b"},
+			expected: `{"a,b"}`,
+		},
+		{
+			name:     "integer elements (JSON float64)",
+			input:    []interface{}{float64(1), float64(2), float64(3)},
+			expected: "{1,2,3}",
+		},
+		{
+			name:     "bool elements",
+			input:    []interface{}{true, false},
+			expected: "{t,f}",
+		},
+		{
+			name:     "nil input passthrough",
+			input:    nil,
+			expected: nil,
+		},
+		{
+			name:     "string input passthrough",
+			input:    "hello",
+			expected: "hello",
+		},
+		{
+			name:     "int input passthrough",
+			input:    42,
+			expected: 42,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ConvertSliceForBun(tt.input)
+			if result != tt.expected {
+				t.Errorf("ConvertSliceForBun(%v) = %v; want %v", tt.input, result, tt.expected)
+			}
+		})
+	}
+}

pkg/common/interfaces.go

@@ -75,6 +75,7 @@ type InsertQuery interface {
 
 	// Execution
 	Exec(ctx context.Context) (Result, error)
+	Scan(ctx context.Context, dest interface{}) error
 }
 
 // UpdateQuery interface for building UPDATE queries

pkg/common/recursive_crud.go

@@ -234,27 +234,32 @@ func (p *NestedCUDProcessor) injectForeignKeys(data map[string]interface{}, mode
 		return
 	}
 
-	// Iterate through model fields to find foreign key fields
+	for parentKey, parentID := range parentIDs {
-	for i := 0; i < modelType.NumField(); i++ {
+		dbColName := reflection.GetForeignKeyColumn(modelType, parentKey)
-		field := modelType.Field(i)
-		jsonTag := field.Tag.Get("json")
-		jsonName := strings.Split(jsonTag, ",")[0]
 
-		// Check if this field is a foreign key and we have a parent ID for it
+		if dbColName == "" {
-		// Common patterns: DepartmentID, ManagerID, ProjectID, etc.
+			// No explicit tag found — fall back to naming convention by scanning scalar fields.
-		for parentKey, parentID := range parentIDs {
+			for i := 0; i < modelType.NumField(); i++ {
-			// Match field name patterns like "department_id" with parent key "department"
+				field := modelType.Field(i)
-			if strings.EqualFold(jsonName, parentKey+"_id") ||
+				jsonName := strings.Split(field.Tag.Get("json"), ",")[0]
-				strings.EqualFold(jsonName, parentKey+"id") ||
+				if strings.EqualFold(jsonName, "rid"+parentKey) ||
-				strings.EqualFold(field.Name, parentKey+"ID") {
+					strings.EqualFold(jsonName, "rid_"+parentKey) ||
-				// Use the DB column name as the key, since data is keyed by DB column names
+					strings.EqualFold(jsonName, "id_"+parentKey) ||
-				dbColName := reflection.GetColumnName(field)
+					strings.EqualFold(jsonName, parentKey+"_id") ||
-				if _, exists := data[dbColName]; !exists {
+					strings.EqualFold(jsonName, parentKey+"id") ||
-					logger.Debug("Injecting foreign key: %s = %v", dbColName, parentID)
+					strings.EqualFold(field.Name, parentKey+"ID") {
-					data[dbColName] = parentID
+					dbColName = reflection.GetColumnName(field)
+					break
 				}
 			}
 		}
+
+		if dbColName != "" {
+			if _, exists := data[dbColName]; !exists {
+				logger.Debug("Injecting foreign key: %s = %v", dbColName, parentID)
+				data[dbColName] = parentID
+			}
+		}
 	}
 }
 
@@ -269,27 +274,18 @@ func (p *NestedCUDProcessor) processInsert(
 	query := p.db.NewInsert().Table(tableName)
 
 	for key, value := range data {
-		query = query.Value(key, value)
+		query = query.Value(key, ConvertSliceForBun(value))
 	}
 	pkName := reflection.GetPrimaryKeyName(tableName)
-	// Add RETURNING clause to get the inserted ID
 	query = query.Returning(pkName)
 
-	result, err := query.Exec(ctx)
+	var id interface{}
-	if err != nil {
+	if err := query.Scan(ctx, &id); err != nil {
 		logger.Error("Insert execution failed: table=%s, data=%+v, error=%v", tableName, data, err)
 		return nil, fmt.Errorf("insert exec failed: %w", err)
 	}
 
-	// Try to get the ID
+	logger.Debug("Insert successful, ID: %v", id)
-	var id interface{}
-	if lastID, err := result.LastInsertId(); err == nil && lastID > 0 {
-		id = lastID
-	} else if data[pkName] != nil {
-		id = data[pkName]
-	}
-
-	logger.Debug("Insert successful, ID: %v, rows affected: %d", id, result.RowsAffected())
 	return id, nil
 }
 

pkg/common/recursive_crud_test.go

@@ -101,12 +101,18 @@ func (m *mockInsertQuery) Value(column string, value interface{}) InsertQuery {
 func (m *mockInsertQuery) OnConflict(action string) InsertQuery { return m }
 func (m *mockInsertQuery) Returning(columns ...string) InsertQuery { return m }
 func (m *mockInsertQuery) Exec(ctx context.Context) (Result, error) {
-	// Record the insert call
 	m.db.insertCalls = append(m.db.insertCalls, m.values)
 	m.db.lastID++
 	return &mockResult{lastID: m.db.lastID, rowsAffected: 1}, nil
 }
 
+func (m *mockInsertQuery) Scan(ctx context.Context, dest interface{}) error {
+	m.db.insertCalls = append(m.db.insertCalls, m.values)
+	m.db.lastID++
+	reflect.ValueOf(dest).Elem().Set(reflect.ValueOf(m.db.lastID))
+	return nil
+}
+
 // Mock UpdateQuery
 type mockUpdateQuery struct {
 	db        *mockDatabase

pkg/common/sql_helpers.go

@@ -59,6 +59,38 @@ func IsSQLExpression(cond string) bool {
 	return false
 }
 
+// reEmptyCompMid matches a simple column comparison with an empty RHS that is immediately
+// followed by AND/OR (only whitespace between the operator and the next keyword).
+// Removing the match leaves the preceding AND/OR connector intact.
+// Example: "cond1 and col = \n    and cond2" → "cond1 and cond2"
+var reEmptyCompMid = regexp.MustCompile(`(?i)[\w.]+\s*(?:=|<>|!=|>=|<=|>|<)\s+(?:and|or)\s+`)
+
+// reEmptyCompEnd matches AND/OR + a simple column comparison with an empty RHS at the end
+// of the string (or sub-clause).
+// Example: "cond1 and col = " → "cond1"
+var reEmptyCompEnd = regexp.MustCompile(`(?i)\s+(?:and|or)\s+[\w.]+\s*(?:=|<>|!=|>=|<=|>|<)\s*$`)
+
+// stripEmptyComparisonClauses removes comparison conditions that have no right-hand side
+// value from a raw SQL string. Operates on the whole string so it also cleans up conditions
+// inside subqueries, not just top-level AND splits.
+func stripEmptyComparisonClauses(sql string) string {
+	sql = reEmptyCompMid.ReplaceAllLiteralString(sql, "")
+	sql = reEmptyCompEnd.ReplaceAllLiteralString(sql, "")
+	return sql
+}
+
+// hasEmptyRHS returns true when a condition ends with a comparison operator and has no
+// right-hand side value — e.g., "col = ", "com.rid_parent = ", "col >= ".
+func hasEmptyRHS(cond string) bool {
+	cond = strings.TrimSpace(cond)
+	for _, op := range []string{"<>", "!=", ">=", "<=", "=", ">", "<"} {
+		if strings.HasSuffix(cond, op) {
+			return true
+		}
+	}
+	return false
+}
+
 // IsTrivialCondition checks if a condition is trivial and always evaluates to true
 // These conditions should be removed from WHERE clauses as they have no filtering effect
 func IsTrivialCondition(cond string) bool {
@@ -147,6 +179,14 @@ func SanitizeWhereClause(where string, tableName string, options ...*RequestOpti
 		return ""
 	}
 
+	// Strip comparison conditions with empty RHS throughout the SQL string (including
+	// inside subqueries), before condition splitting.
+	where = stripEmptyComparisonClauses(where)
+	if where == "" {
+		return ""
+	}
+	where = strings.TrimSpace(where)
+
 	// Check if the original clause has outer parentheses and contains OR operators
 	// If so, we need to preserve the outer parentheses to prevent OR logic from escaping
 	hasOuterParens := false
@@ -212,6 +252,12 @@ func SanitizeWhereClause(where string, tableName string, options ...*RequestOpti
 			continue
 		}
 
+		// Skip conditions with no right-hand side value (e.g. "col = " with empty value)
+		if hasEmptyRHS(condToCheck) {
+			logger.Debug("Removing condition with empty value: '%s'", cond)
+			continue
+		}
+
 		// If tableName is provided and the condition HAS a table prefix, check if it's correct
 		if tableName != "" && hasTablePrefix(condToCheck) {
 			// Extract the current prefix and column name

pkg/common/sql_helpers_test.go

@@ -134,6 +134,30 @@ func TestSanitizeWhereClause(t *testing.T) {
 			tableName: "apiprovider",
 			expected:  "apiprovider.type in ('softphone') AND (apiprovider.rid_apiprovider in (select l.rid_apiprovider from core.apiproviderlink l where l.rid_hub = 2576))",
 		},
+		{
+			name:      "empty RHS stripped mid-clause",
+			where:     "com.tableprefix = 'tcli' and com.rid_parent = \n    and com.status = 'Active'",
+			tableName: "",
+			expected:  "com.tableprefix = 'tcli' AND com.status = 'Active'",
+		},
+		{
+			name:      "empty RHS stripped at end of clause",
+			where:     "com.tableprefix = 'tcli' and com.rid_parent =",
+			tableName: "",
+			expected:  "com.tableprefix = 'tcli'",
+		},
+		{
+			name:      "non-empty value not stripped",
+			where:     "com.tableprefix = 'tcli' and com.rid_parent = 123 and com.status = 'Active'",
+			tableName: "",
+			expected:  "com.tableprefix = 'tcli' AND com.rid_parent = 123 AND com.status = 'Active'",
+		},
+		{
+			name:      "empty RHS inside subquery stripped",
+			where:     "a = 1 and b in (select x from t where c.rid = \n    and d = 2)",
+			tableName: "",
+			expected:  "a = 1 AND b in (select x from t where d = 2)",
+		},
 	}
 
 	for _, tt := range tests {

pkg/funcspec/function_api.go

@@ -168,9 +168,16 @@ func (h *Handler) SqlQueryList(sqlquery string, options SqlQueryOptions) HTTPFun
 		// Replace meta variables in SQL
 		sqlquery = h.replaceMetaVariables(sqlquery, r, userCtx, metainfo, variables)
 
-		// Remove unused input variables
+		// Replace variables from provided values, then blank any remaining unused ones
-		if options.BlankParams {
+		for _, kw := range inputvars {
-			for _, kw := range inputvars {
+			varName := kw[1 : len(kw)-1] // strip [ and ]
+			if val, ok := variables[varName]; ok {
+				if strVal := fmt.Sprintf("%v", val); strVal != "" {
+					sqlquery = strings.ReplaceAll(sqlquery, kw, ValidSQL(strVal, "colvalue"))
+					continue
+				}
+			}
+			if options.BlankParams {
 				replacement := getReplacementForBlankParam(sqlquery, kw)
 				sqlquery = strings.ReplaceAll(sqlquery, kw, replacement)
 				logger.Debug("Replaced unused variable %s with: %s", kw, replacement)
@@ -520,9 +527,16 @@ func (h *Handler) SqlQuery(sqlquery string, options SqlQueryOptions) HTTPFuncTyp
 			}
 		}
 
-		// Remove unused input variables
+		// Replace variables from provided values, then blank any remaining unused ones
-		if options.BlankParams {
+		for _, kw := range inputvars {
-			for _, kw := range inputvars {
+			varName := kw[1 : len(kw)-1] // strip [ and ]
+			if val, ok := variables[varName]; ok {
+				if strVal := fmt.Sprintf("%v", val); strVal != "" {
+					sqlquery = strings.ReplaceAll(sqlquery, kw, ValidSQL(strVal, "colvalue"))
+					continue
+				}
+			}
+			if options.BlankParams {
 				replacement := getReplacementForBlankParam(sqlquery, kw)
 				sqlquery = strings.ReplaceAll(sqlquery, kw, replacement)
 				logger.Debug("Replaced unused variable %s with: %s", kw, replacement)
@@ -715,8 +729,10 @@ func (h *Handler) mergeQueryParams(r *http.Request, sqlquery string, variables m
 			propQry[parmk] = val
 		}
 
-		// Apply filters if allowed
+		// Apply filters if allowed — check only the SELECT list to avoid matching function
-		if allowFilter && len(parmk) > 1 && strings.Contains(strings.ToLower(sqlquery), strings.ToLower(parmk)) {
+		// parameters in the FROM clause (e.g. [p_rid_doctype] in a set-returning function call)
+		// or names inside quoted string arguments.
+		if allowFilter && len(parmk) > 1 && strings.Contains(sqlSelectList(sqlStripStringLiterals(sqlquery)), strings.ToLower(parmk)) {
 			if len(parmv) > 1 {
 				// Sanitize each value in the IN clause with appropriate quoting
 				sanitizedValues := make([]string, len(parmv))
@@ -824,6 +840,26 @@ func (h *Handler) mergeHeaderParams(r *http.Request, sqlquery string, variables
 	return sqlquery
 }
 
+// sqlStripStringLiterals removes the contents of single-quoted string literals from SQL,
+// leaving the structural identifiers (column names, table names) intact.
+// Used to check column presence without matching inside string arguments.
+func sqlStripStringLiterals(sql string) string {
+	re := regexp.MustCompile(`'(?:[^']|'')*'`)
+	return re.ReplaceAllString(sql, "''")
+}
+
+// sqlSelectList returns the column list portion of a SELECT query (between SELECT and FROM).
+// Returns the full query lowercased if no clear SELECT…FROM boundary is found.
+func sqlSelectList(sql string) string {
+	lower := strings.ToLower(sql)
+	selectPos := strings.Index(lower, "select ")
+	fromPos := strings.Index(lower, " from ")
+	if selectPos < 0 || fromPos <= selectPos {
+		return lower
+	}
+	return lower[selectPos+7 : fromPos]
+}
+
 // replaceMetaVariables replaces meta variables like [rid_user], [user], etc. in the SQL query
 func (h *Handler) replaceMetaVariables(sqlquery string, r *http.Request, userCtx *security.UserContext, metainfo map[string]interface{}, variables map[string]interface{}) string {
 	if strings.Contains(sqlquery, "[p_meta_default]") {
@@ -991,8 +1027,8 @@ func getReplacementForBlankParam(sqlquery, param string) string {
 		charAfter = sqlquery[endIdx]
 	}
 
-	// Check if parameter is surrounded by quotes (single quote or dollar sign for PostgreSQL dollar-quoted strings)
+	// Check if parameter is surrounded by quotes (single quote, dollar sign for PostgreSQL dollar-quoted strings, or double quote for JSON string values)
-	if (charBefore == '\'' || charBefore == '$') && (charAfter == '\'' || charAfter == '$') {
+	if (charBefore == '\'' || charBefore == '$' || charBefore == '"') && (charAfter == '\'' || charAfter == '$' || charAfter == '"') {
 		// Parameter is in quotes, return empty string
 		return ""
 	}

pkg/funcspec/function_api_test.go

@@ -821,7 +821,7 @@ func TestReplaceMetaVariables(t *testing.T) {
 			name:     "Replace [user]",
 			sqlQuery: "SELECT * FROM audit WHERE username = [user]",
 			expectedCheck: func(result string) bool {
-				return strings.Contains(result, "'testuser'")
+				return strings.Contains(result, "$USR$testuser$USR$")
 			},
 		},
 		{
@@ -851,6 +851,285 @@ func TestReplaceMetaVariables(t *testing.T) {
 	}
 }
 
+// TestSqlStripStringLiterals tests that single-quoted string literals are removed
+func TestSqlStripStringLiterals(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "No string literals",
+			input:    "SELECT rid, rid_parent FROM users",
+			expected: "SELECT rid, rid_parent FROM users",
+		},
+		{
+			name:     "Simple string literal",
+			input:    "SELECT * FROM users WHERE mode = 'admin'",
+			expected: "SELECT * FROM users WHERE mode = ''",
+		},
+		{
+			name:     "JSON argument containing column names",
+			input:    `SELECT rid, rid_parent FROM crm_get_menu(1,'mode', '{"rid_parent":"[rid_parent]","CF:STARTDATE":"[cf_startdate]"}')`,
+			expected: `SELECT rid, rid_parent FROM crm_get_menu(1,'', '')`,
+		},
+		{
+			name:     "Escaped single quotes inside literal",
+			input:    "SELECT * FROM t WHERE name = 'O''Brien'",
+			expected: "SELECT * FROM t WHERE name = ''",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := sqlStripStringLiterals(tt.input)
+			if result != tt.expected {
+				t.Errorf("sqlStripStringLiterals() =\n  %q\nwant\n  %q", result, tt.expected)
+			}
+		})
+	}
+}
+
+// TestAllowFilterDoesNotMatchInsideJsonArgument verifies that AllowFilter will add WHERE
+// clauses for real output columns (rid, rid_parent) but not for names that only appear
+// inside a JSON string argument (cf_startdate, cf_rid_branch).
+func TestAllowFilterDoesNotMatchInsideJsonArgument(t *testing.T) {
+	handler := NewHandler(&MockDatabase{})
+
+	sqlQuery := `select rid, rid_parent, description
+      from crm_get_menu([rid_user],'[p_mode]', 0, '', '{"rid_parent":"[rid_parent]", "CF:STARTDATE": "[cf_startdate]", "CF:RID_BRANCH": "[cf_rid_branch]"}')`
+
+	tests := []struct {
+		name        string
+		queryParams map[string]string
+		checkResult func(t *testing.T, result string)
+	}{
+		{
+			name:        "rid_parent=0 is a real column — filter applied",
+			queryParams: map[string]string{"rid_parent": "0"},
+			checkResult: func(t *testing.T, result string) {
+				if !strings.Contains(strings.ToLower(result), "where") {
+					t.Error("Expected WHERE clause to be added for rid_parent")
+				}
+				if !strings.Contains(result, "rid_parent = 0 OR") && !strings.Contains(result, "rid_parent IS NULL") {
+					t.Errorf("Expected null-safe filter for rid_parent=0, got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "cf_startdate only appears in JSON string — no filter applied",
+			queryParams: map[string]string{"cf_startdate": "2024-01-01"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(strings.ToLower(result), "where") {
+					t.Errorf("Expected no WHERE clause for cf_startdate (only in JSON arg), got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "cf_rid_branch only appears in JSON string — no filter applied",
+			queryParams: map[string]string{"cf_rid_branch": "5"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(strings.ToLower(result), "where") {
+					t.Errorf("Expected no WHERE clause for cf_rid_branch (only in JSON arg), got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "description is a real column — filter applied",
+			queryParams: map[string]string{"description": "test"},
+			checkResult: func(t *testing.T, result string) {
+				if !strings.Contains(strings.ToLower(result), "where") {
+					t.Error("Expected WHERE clause for description")
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := createTestRequest("GET", "/test", tt.queryParams, nil, nil)
+			variables := make(map[string]interface{})
+			propQry := make(map[string]string)
+
+			result := handler.mergeQueryParams(req, sqlQuery, variables, true, propQry)
+			tt.checkResult(t, result)
+		})
+	}
+}
+
+// TestAllowFilterDoesNotMatchFunctionParams verifies that query params that appear only
+// as function call arguments in the FROM clause (e.g. [p_rid_doctype]) are not treated
+// as column filters, since they are not in the SELECT list.
+func TestAllowFilterDoesNotMatchFunctionParams(t *testing.T) {
+	handler := NewHandler(&MockDatabase{})
+
+	sqlQuery := `select rid, rid_parent, description, row_cnt, filterstring, tableprefix, rid_table, tooltip, additionalfilter, haschildren
+    from crm_get_doc_menu($JQ$[p_tableprefix]$JQ$,[p_rid_parent],[p_rid_doctype],[p_removedup],[p_showall]) r`
+
+	tests := []struct {
+		name        string
+		queryParams map[string]string
+		checkResult func(t *testing.T, result string)
+	}{
+		{
+			name:        "p_rid_doctype is a function param, not a column — no filter applied",
+			queryParams: map[string]string{"p_rid_doctype": "0"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(strings.ToLower(result), "where") {
+					t.Errorf("Expected no WHERE clause for p_rid_doctype (function arg, not SELECT column), got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "p_showall is a function param, not a column — no filter applied",
+			queryParams: map[string]string{"p_showall": "1"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(strings.ToLower(result), "where") {
+					t.Errorf("Expected no WHERE clause for p_showall (function arg, not SELECT column), got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "rid is a SELECT column — filter applied",
+			queryParams: map[string]string{"rid": "42"},
+			checkResult: func(t *testing.T, result string) {
+				if !strings.Contains(strings.ToLower(result), "where") {
+					t.Error("Expected WHERE clause for rid (real SELECT column)")
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := createTestRequest("GET", "/test", tt.queryParams, nil, nil)
+			variables := make(map[string]interface{})
+			propQry := make(map[string]string)
+			result := handler.mergeQueryParams(req, sqlQuery, variables, true, propQry)
+			tt.checkResult(t, result)
+		})
+	}
+}
+
+// TestGetReplacementForBlankParamDoubleQuote verifies that placeholders surrounded by
+// double quotes (as in JSON string values) are blanked to "" not NULL.
+func TestGetReplacementForBlankParamDoubleQuote(t *testing.T) {
+	tests := []struct {
+		name     string
+		sqlQuery string
+		param    string
+		expected string
+	}{
+		{
+			name:     "Parameter in double quotes (JSON value)",
+			sqlQuery: `SELECT * FROM f(1, '{"key":"[myparam]"}')`,
+			param:    "[myparam]",
+			expected: "",
+		},
+		{
+			name:     "Parameter not in any quotes",
+			sqlQuery: `SELECT * FROM f([myparam])`,
+			param:    "[myparam]",
+			expected: "NULL",
+		},
+		{
+			name:     "Parameter in single quotes",
+			sqlQuery: `SELECT * FROM f('[myparam]')`,
+			param:    "[myparam]",
+			expected: "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := getReplacementForBlankParam(tt.sqlQuery, tt.param)
+			if result != tt.expected {
+				t.Errorf("getReplacementForBlankParam() = %q, want %q\nquery: %s", result, tt.expected, tt.sqlQuery)
+			}
+		})
+	}
+}
+
+// TestVariableReplacementFromQueryParams verifies that query params matching [placeholder]
+// tokens are substituted even when they don't have the p- prefix.
+func TestVariableReplacementFromQueryParams(t *testing.T) {
+	handler := NewHandler(&MockDatabase{})
+
+	sqlQuery := `select rid, rid_parent from crm_get_menu([rid_user],'[p_mode]', 0, '', '{"rid_parent":"[rid_parent]","CF:STARTDATE":"[cf_startdate]"}')`
+
+	tests := []struct {
+		name        string
+		queryParams map[string]string
+		checkResult func(t *testing.T, result string)
+	}{
+		{
+			name:        "rid_parent replaced from query param",
+			queryParams: map[string]string{"rid_parent": "42"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(result, "[rid_parent]") {
+					t.Errorf("Expected [rid_parent] to be replaced, still present in:\n%s", result)
+				}
+				if !strings.Contains(result, "42") {
+					t.Errorf("Expected value 42 in query, got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "cf_startdate replaced from query param",
+			queryParams: map[string]string{"cf_startdate": "2024-01-01"},
+			checkResult: func(t *testing.T, result string) {
+				if strings.Contains(result, "[cf_startdate]") {
+					t.Errorf("Expected [cf_startdate] to be replaced, still present in:\n%s", result)
+				}
+				if !strings.Contains(result, "2024-01-01") {
+					t.Errorf("Expected date value in query, got:\n%s", result)
+				}
+			},
+		},
+		{
+			name:        "missing param blanked to empty string inside JSON (double-quoted)",
+			queryParams: map[string]string{},
+			checkResult: func(t *testing.T, result string) {
+				// [cf_startdate] is surrounded by " in the JSON — should blank to ""
+				if strings.Contains(result, "[cf_startdate]") {
+					t.Errorf("Expected [cf_startdate] to be blanked, still present in:\n%s", result)
+				}
+				if strings.Contains(result, "NULL") && strings.Contains(result, "cf_startdate") {
+					t.Errorf("Expected empty string (not NULL) for double-quoted placeholder, got:\n%s", result)
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			inputvars := make([]string, 0)
+			q := handler.extractInputVariables(sqlQuery, &inputvars)
+
+			req := createTestRequest("GET", "/test", tt.queryParams, nil, nil)
+			variables := make(map[string]interface{})
+			propQry := make(map[string]string)
+
+			q = handler.mergeQueryParams(req, q, variables, false, propQry)
+
+			// Simulate the variable replacement + blank-param loop (mirrors function_api.go)
+			for _, kw := range inputvars {
+				varName := kw[1 : len(kw)-1]
+				if val, ok := variables[varName]; ok {
+					if strVal := strings.TrimSpace(val.(string)); strVal != "" {
+						q = strings.ReplaceAll(q, kw, ValidSQL(strVal, "colvalue"))
+						continue
+					}
+				}
+				replacement := getReplacementForBlankParam(q, kw)
+				q = strings.ReplaceAll(q, kw, replacement)
+			}
+
+			tt.checkResult(t, q)
+		})
+	}
+}
+
 // TestGetReplacementForBlankParam tests the blank parameter replacement logic
 func TestGetReplacementForBlankParam(t *testing.T) {
 	tests := []struct {

pkg/reflection/helpers.go

@@ -76,9 +76,14 @@ func GetJSONNameForField(modelType reflect.Type, fieldName string) string {
 		return ""
 	}
 
-	// Handle pointer types
+	// Unwrap pointer and slice indirections to reach the struct type
-	if modelType.Kind() == reflect.Ptr {
+	for {
-		modelType = modelType.Elem()
+		switch modelType.Kind() {
+		case reflect.Ptr, reflect.Slice:
+			modelType = modelType.Elem()
+			continue
+		}
+		break
 	}
 
 	if modelType.Kind() != reflect.Struct {

pkg/reflection/model_utils.go

@@ -541,9 +541,14 @@ func collectSQLColumnsFromType(typ reflect.Type, columns *[]string, scanOnlyEmbe
 func IsColumnWritable(model any, columnName string) bool {
 	modelType := reflect.TypeOf(model)
 
-	// Unwrap pointers to get to the base struct type
+	// Unwrap pointers and slices to get to the base struct type
-	for modelType != nil && modelType.Kind() == reflect.Pointer {
+	for modelType != nil {
-		modelType = modelType.Elem()
+		switch modelType.Kind() {
+		case reflect.Ptr, reflect.Slice:
+			modelType = modelType.Elem()
+			continue
+		}
+		break
 	}
 
 	// Validate that we have a struct type
@@ -878,8 +883,14 @@ func GetRelationType(model interface{}, fieldName string) RelationType {
 		return RelationUnknown
 	}
 
-	if modelType.Kind() == reflect.Ptr {
+	// Unwrap pointer → slice → pointer chains to reach the underlying struct
-		modelType = modelType.Elem()
+	for {
+		switch modelType.Kind() {
+		case reflect.Ptr, reflect.Slice:
+			modelType = modelType.Elem()
+			continue
+		}
+		break
 	}
 
 	if modelType == nil || modelType.Kind() != reflect.Struct {
@@ -962,6 +973,62 @@ func GetRelationType(model interface{}, fieldName string) RelationType {
 	return RelationUnknown
 }
 
+// GetForeignKeyColumn returns the DB column name of the foreign key that the
+// relation field identified by parentKey owns on modelType.
+//
+// It checks tags in priority order:
+//  1. Bun join: tag — e.g. `bun:"rel:belongs-to,join:department_id=id"` → "department_id"
+//  2. GORM foreignKey: tag — e.g. `gorm:"foreignKey:DepartmentID"` → column of DepartmentID field
+//  3. Returns "" when no tag is found (caller should fall back to convention)
+//
+// parentKey is matched case-insensitively against the field name and JSON tag.
+func GetForeignKeyColumn(modelType reflect.Type, parentKey string) string {
+	for modelType.Kind() == reflect.Ptr || modelType.Kind() == reflect.Slice {
+		modelType = modelType.Elem()
+	}
+	if modelType.Kind() != reflect.Struct {
+		return ""
+	}
+
+	for i := 0; i < modelType.NumField(); i++ {
+		field := modelType.Field(i)
+
+		name := field.Name
+		jsonName := strings.Split(field.Tag.Get("json"), ",")[0]
+		if !strings.EqualFold(name, parentKey) && !strings.EqualFold(jsonName, parentKey) {
+			continue
+		}
+
+		// Bun: join:local_col=foreign_col
+		for _, part := range strings.Split(field.Tag.Get("bun"), ",") {
+			part = strings.TrimSpace(part)
+			if strings.HasPrefix(part, "join:") {
+				// join: may contain multiple pairs separated by spaces: "join:a=b join:c=d"
+				// but typically it's a single pair; take the first local column
+				pair := strings.TrimPrefix(part, "join:")
+				if idx := strings.Index(pair, "="); idx > 0 {
+					return pair[:idx]
+				}
+			}
+		}
+
+		// GORM: foreignKey:FieldName
+		for _, part := range strings.Split(field.Tag.Get("gorm"), ";") {
+			part = strings.TrimSpace(part)
+			if strings.HasPrefix(part, "foreignKey:") {
+				fkFieldName := strings.TrimPrefix(part, "foreignKey:")
+				if fkField, ok := modelType.FieldByName(fkFieldName); ok {
+					return getColumnNameFromField(fkField)
+				}
+			}
+		}
+
+		return ""
+	}
+
+	return ""
+}
+
 // GetRelationModel gets the model type for a relation field
 // It searches for the field by name in the following order (case-insensitive):
 // 1. Actual field name
@@ -1472,9 +1539,14 @@ func convertToFloat64(value interface{}) (float64, bool) {
 func GetValidJSONFieldNames(modelType reflect.Type) map[string]bool {
 	validFields := make(map[string]bool)
 
-	// Unwrap pointers to get to the base struct type
+	// Unwrap pointers and slices to get to the base struct type
-	for modelType != nil && modelType.Kind() == reflect.Pointer {
+	for modelType != nil {
-		modelType = modelType.Elem()
+		switch modelType.Kind() {
+		case reflect.Ptr, reflect.Slice:
+			modelType = modelType.Elem()
+			continue
+		}
+		break
 	}
 
 	if modelType == nil || modelType.Kind() != reflect.Struct {
@@ -1535,8 +1607,13 @@ func getRelationModelSingleLevel(model interface{}, fieldName string) interface{
 		return nil
 	}
 
-	if modelType.Kind() == reflect.Ptr {
+	for {
-		modelType = modelType.Elem()
+		switch modelType.Kind() {
+		case reflect.Ptr, reflect.Slice:
+			modelType = modelType.Elem()
+			continue
+		}
+		break
 	}
 
 	if modelType == nil || modelType.Kind() != reflect.Struct {
@@ -1599,17 +1676,16 @@ func getRelationModelSingleLevel(model interface{}, fieldName string) interface{
 		return nil
 	}
 
-	if targetType.Kind() == reflect.Slice {
+	for {
-		targetType = targetType.Elem()
+		switch targetType.Kind() {
-		if targetType == nil {
+		case reflect.Ptr, reflect.Slice:
-			return nil
+			targetType = targetType.Elem()
-		}
+			if targetType == nil {
-	}
+				return nil
-	if targetType.Kind() == reflect.Ptr {
+			}
-		targetType = targetType.Elem()
+			continue
-		if targetType == nil {
-			return nil
 		}
+		break
 	}
 
 	if targetType.Kind() != reflect.Struct {

pkg/reflection/model_utils_foreign_key_test.go

@@ -0,0 +1,123 @@
+package reflection
+
+import (
+	"reflect"
+	"testing"
+)
+
+// --- local test models ---
+
+type fkDept struct{}
+
+// bunEmployee uses bun join: tag to declare the FK column explicitly.
+type bunEmployee struct {
+	DeptID     string   `bun:"dept_id"                          json:"dept_id"`
+	Department *fkDept  `bun:"rel:belongs-to,join:dept_id=id"   json:"department"`
+}
+
+// gormEmployee uses gorm foreignKey: tag (mirrors testmodels.Employee).
+type gormEmployee struct {
+	DepartmentID string  `json:"department_id"`
+	ManagerID    string  `json:"manager_id"`
+	Department   *fkDept `gorm:"foreignKey:DepartmentID;references:ID" json:"department"`
+	Manager      *fkDept `gorm:"foreignKey:ManagerID;references:ID"    json:"manager"`
+}
+
+// conventionEmployee has no explicit FK tag — relies on naming convention.
+type conventionEmployee struct {
+	DepartmentID string  `json:"department_id"`
+	Department   *fkDept `json:"department"`
+}
+
+// noTagEmployee has a relation field with no FK tag and no convention match.
+type noTagEmployee struct {
+	Unrelated *fkDept `json:"unrelated"`
+}
+
+func TestGetForeignKeyColumn(t *testing.T) {
+	tests := []struct {
+		name      string
+		modelType reflect.Type
+		parentKey string
+		want      string
+	}{
+		// Bun join: tag
+		{
+			name:      "bun join tag returns local column",
+			modelType: reflect.TypeOf(bunEmployee{}),
+			parentKey: "department",
+			want:      "dept_id",
+		},
+		{
+			name:      "bun join tag matched via json tag (case-insensitive)",
+			modelType: reflect.TypeOf(bunEmployee{}),
+			parentKey: "Department",
+			want:      "dept_id",
+		},
+
+		// GORM foreignKey: tag
+		{
+			name:      "gorm foreignKey resolves to column name",
+			modelType: reflect.TypeOf(gormEmployee{}),
+			parentKey: "department",
+			want:      "department_id",
+		},
+		{
+			name:      "gorm foreignKey resolves second relation",
+			modelType: reflect.TypeOf(gormEmployee{}),
+			parentKey: "manager",
+			want:      "manager_id",
+		},
+		{
+			name:      "gorm foreignKey matched case-insensitively",
+			modelType: reflect.TypeOf(gormEmployee{}),
+			parentKey: "Department",
+			want:      "department_id",
+		},
+
+		// Pointer and slice unwrapping
+		{
+			name:      "pointer to struct is unwrapped",
+			modelType: reflect.TypeOf(&gormEmployee{}),
+			parentKey: "department",
+			want:      "department_id",
+		},
+		{
+			name:      "slice of struct is unwrapped",
+			modelType: reflect.TypeOf([]gormEmployee{}),
+			parentKey: "department",
+			want:      "department_id",
+		},
+
+		// No tag — returns "" so caller can fall back to convention
+		{
+			name:      "relation with no FK tag returns empty string",
+			modelType: reflect.TypeOf(conventionEmployee{}),
+			parentKey: "department",
+			want:      "",
+		},
+
+		// Unknown parent key
+		{
+			name:      "unknown parent key returns empty string",
+			modelType: reflect.TypeOf(gormEmployee{}),
+			parentKey: "nonexistent",
+			want:      "",
+		},
+		{
+			name:      "non-struct type returns empty string",
+			modelType: reflect.TypeOf(""),
+			parentKey: "department",
+			want:      "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetForeignKeyColumn(tt.modelType, tt.parentKey)
+			if got != tt.want {
+				t.Errorf("GetForeignKeyColumn(%v, %q) = %q, want %q", tt.modelType, tt.parentKey, got, tt.want)
+			}
+		})
+	}
+}

pkg/resolvespec/handler.go

@@ -603,7 +603,7 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 		// Standard processing without nested relations
 		query := h.db.NewInsert().Table(tableName)
 		for key, value := range v {
-			query = query.Value(key, value)
+			query = query.Value(key, common.ConvertSliceForBun(value))
 		}
 		result, err := query.Exec(ctx)
 		if err != nil {
@@ -669,7 +669,7 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 			for _, item := range v {
 				txQuery := tx.NewInsert().Table(tableName)
 				for key, value := range item {
-					txQuery = txQuery.Value(key, value)
+					txQuery = txQuery.Value(key, common.ConvertSliceForBun(value))
 				}
 				if _, err := txQuery.Exec(ctx); err != nil {
 					return err
@@ -747,7 +747,7 @@ func (h *Handler) handleCreate(ctx context.Context, w common.ResponseWriter, dat
 				if itemMap, ok := item.(map[string]interface{}); ok {
 					txQuery := tx.NewInsert().Table(tableName)
 					for key, value := range itemMap {
-						txQuery = txQuery.Value(key, value)
+						txQuery = txQuery.Value(key, common.ConvertSliceForBun(value))
 					}
 					if _, err := txQuery.Exec(ctx); err != nil {
 						return err

pkg/restheadspec/handler.go

@@ -575,11 +575,25 @@ func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, id st
 		}
 	}
 
-	// Apply custom SQL JOIN clauses
+	// Apply custom SQL JOIN clauses, skipping any whose alias is already provided by a
+	// preload LEFT JOIN (to prevent "table name specified more than once" errors).
 	if len(options.CustomSQLJoin) > 0 {
-		for _, joinClause := range options.CustomSQLJoin {
+		preloadAliasSet := make(map[string]bool, len(options.Preload))
+		for _, p := range options.Preload {
+			if alias := common.RelationPathToBunAlias(p.Relation); alias != "" {
+				preloadAliasSet[alias] = true
+			}
+		}
+
+		for i, joinClause := range options.CustomSQLJoin {
+			if i < len(options.JoinAliases) && options.JoinAliases[i] != "" {
+				alias := strings.ToLower(options.JoinAliases[i])
+				if preloadAliasSet[alias] {
+					logger.Debug("Skipping custom SQL JOIN (alias '%s' already joined by preload): %s", alias, joinClause)
+					continue
+				}
+			}
 			logger.Debug("Applying custom SQL JOIN: %s", joinClause)
-			// Joins are already sanitized during parsing, so we can apply them directly
 			query = query.Join(joinClause)
 		}
 	}

pkg/restheadspec/headers.go

@@ -5,8 +5,10 @@ import (
 	"encoding/json"
 	"fmt"
 	"reflect"
+	"regexp"
 	"strconv"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/bitechdev/ResolveSpec/pkg/common"
 	"github.com/bitechdev/ResolveSpec/pkg/logger"
@@ -63,7 +65,10 @@ type ExpandOption struct {
 // decodeHeaderValue decodes base64 encoded header values
 // Supports ZIP_ and __ prefixes for base64 encoding
 func decodeHeaderValue(value string) string {
-	str, _ := DecodeParam(value)
+	str, err := DecodeParam(value)
+	if err != nil {
+		return value
+	}
 	return str
 }
 
@@ -97,6 +102,11 @@ func DecodeParam(pStr string) (string, error) {
 
 	if strings.HasPrefix(code, "ZIP_") || strings.HasPrefix(code, "__") {
 		code, _ = DecodeParam(code)
+	} else {
+		strDat, err := base64.StdEncoding.DecodeString(code)
+		if err == nil && utf8.Valid(strDat) {
+			code = string(strDat)
+		}
 	}
 
 	return code, nil
@@ -501,6 +511,31 @@ func (h *Handler) parseExpand(options *ExtendedRequestOptions, value string) {
 	}
 }
 
+// reMultiJoinBoundary finds the start of each individual JOIN clause within a string that
+// may contain multiple consecutive JOIN clauses (e.g., "INNER JOIN ... LEFT OUTER JOIN ...").
+var reMultiJoinBoundary = regexp.MustCompile(`(?i)(?:inner|left(?:\s+outer)?|right(?:\s+outer)?|full(?:\s+outer)?|cross)\s+join\b`)
+
+// splitJoinClauses splits a SQL string that may contain multiple JOIN clauses into
+// individual clauses. A plain pipe-separated segment may itself contain several JOINs;
+// this function splits them so each gets its own alias entry.
+func splitJoinClauses(joinStr string) []string {
+	indices := reMultiJoinBoundary.FindAllStringIndex(joinStr, -1)
+	if len(indices) <= 1 {
+		return []string{strings.TrimSpace(joinStr)}
+	}
+	parts := make([]string, 0, len(indices))
+	for i, idx := range indices {
+		end := len(joinStr)
+		if i+1 < len(indices) {
+			end = indices[i+1][0]
+		}
+		if part := strings.TrimSpace(joinStr[idx[0]:end]); part != "" {
+			parts = append(parts, part)
+		}
+	}
+	return parts
+}
+
 // parseCustomSQLJoin parses x-custom-sql-join header
 // Format: Single JOIN clause or multiple JOIN clauses separated by |
 // Example: "LEFT JOIN departments d ON d.id = employees.department_id"
@@ -533,17 +568,19 @@ func (h *Handler) parseCustomSQLJoin(options *ExtendedRequestOptions, value stri
 			continue
 		}
 
-		// Extract table alias from the JOIN clause
+		// Split into individual JOIN clauses so each clause gets its own alias entry.
-		alias := extractJoinAlias(sanitizedJoin)
+		// CustomSQLJoin and JoinAliases are kept parallel (one entry per individual clause).
-		if alias != "" {
+		for _, clause := range splitJoinClauses(sanitizedJoin) {
+			alias := extractJoinAlias(clause)
+			// Keep arrays parallel; use empty string when alias cannot be extracted.
 			options.JoinAliases = append(options.JoinAliases, alias)
-			// Also add to the embedded RequestOptions for validation
 			options.RequestOptions.JoinAliases = append(options.RequestOptions.JoinAliases, alias)
-			logger.Debug("Extracted join alias: %s", alias)
+			if alias != "" {
+				logger.Debug("Extracted join alias: %s", alias)
+			}
+			logger.Debug("Adding custom SQL join: %s", clause)
+			options.CustomSQLJoin = append(options.CustomSQLJoin, clause)
 		}
-
-		logger.Debug("Adding custom SQL join: %s", sanitizedJoin)
-		options.CustomSQLJoin = append(options.CustomSQLJoin, sanitizedJoin)
 	}
 }
 

pkg/websocketspec/handler.go

@@ -174,6 +174,7 @@ func (h *Handler) handleRequest(conn *Connection, msg *Message) {
 		Options:    msg.Options,
 		ID:         recordID,
 		Data:       msg.Data,
+		Tx:         h.db,
 		Metadata:   make(map[string]interface{}),
 	}
 

pkg/websocketspec/handler_test.go

@@ -239,6 +239,11 @@ func (m *MockInsertQuery) Exec(ctx context.Context) (common.Result, error) {
 	return args.Get(0).(common.Result), args.Error(1)
 }
 
+func (m *MockInsertQuery) Scan(ctx context.Context, dest interface{}) error {
+	args := m.Called(ctx, dest)
+	return args.Error(0)
+}
+
 // MockUpdateQuery is a mock implementation of common.UpdateQuery
 type MockUpdateQuery struct {
 	mock.Mock

pkg/websocketspec/hooks.go

@@ -111,6 +111,9 @@ type HookContext struct {
 	AbortMessage string // Message to return if aborted
 	AbortCode    int    // HTTP status code if aborted
 
+	// Tx provides access to the database/transaction for executing additional SQL
+	Tx common.Database
+
 	// Metadata is additional context data
 	Metadata map[string]interface{}
 }

todo.md

@@ -92,6 +92,7 @@ See [`resolvespec-python/todo.md`](./resolvespec-python/todo.md) for detailed Py
 
 - [ ] Long preload alias names may exceed PostgreSQL identifier limit
 - [ ] Some edge cases in computed column handling
+- [ ] `GormResult.LastInsertId()` (`pkg/common/adapters/database/gorm.go:936`) always returns `0, nil` — GORM does not expose last insert ID via `sql.Result` for most dialects. Auto-generated IDs from GORM inserts are not propagated back through `LastInsertId`, which breaks the ID-retrieval path in `recursive_crud.go`. Fix: read the ID back from the model struct after `Create()` using reflection, or use GORM's `Statement.LastInsertId`.
 
 ---