feat(security): implement ChainAuthenticator for sequential authentication

Add reflection.IsEmptyValue to detect nil, empty string, and zero numbers.
Use it in recursive CUD processing to skip update/delete when the primary
key is absent, logging a warning instead of proceeding with an invalid operation.

pkg/common/adapters/database/bun.go

@@ -1315,6 +1315,7 @@ func (b *BunSelectQuery) Scan(ctx context.Context, dest interface{}) (err error)
 	if err != nil {
 		sqlStr := b.query.String()
 		logger.Error("BunSelectQuery.Scan failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	return err
 }
@@ -1371,7 +1372,7 @@ func (b *BunSelectQuery) ScanModel(ctx context.Context) (err error) {
 	if err != nil {
 		sqlStr := b.query.String()
 		logger.Error("BunSelectQuery.ScanModel failed. SQL: %s. Error: %v", sqlStr, err)
-		return err
+		return common.WrapSQLError(err, sqlStr)
 	}
 
 	// After main query, load custom preloads using separate queries
@@ -1401,6 +1402,7 @@ func (b *BunSelectQuery) Count(ctx context.Context) (count int, err error) {
 		if err != nil {
 			sqlStr := b.query.String()
 			logger.Error("BunSelectQuery.Count failed. SQL: %s. Error: %v", sqlStr, err)
+			err = common.WrapSQLError(err, sqlStr)
 		}
 		return
 	}
@@ -1414,6 +1416,7 @@ func (b *BunSelectQuery) Count(ctx context.Context) (count int, err error) {
 	if err != nil {
 		sqlStr := countQuery.String()
 		logger.Error("BunSelectQuery.Count (subquery) failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	return
 }
@@ -1431,6 +1434,7 @@ func (b *BunSelectQuery) Exists(ctx context.Context) (exists bool, err error) {
 	if err != nil {
 		sqlStr := b.query.String()
 		logger.Error("BunSelectQuery.Exists failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	return
 }
@@ -1619,6 +1623,7 @@ func (b *BunUpdateQuery) Exec(ctx context.Context) (res common.Result, err error
 		// Log SQL string for debugging
 		sqlStr := b.query.String()
 		logger.Error("BunUpdateQuery.Exec failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(b.metricsEnabled, "UPDATE", b.schema, b.entity, b.tableName, startedAt, err)
 	return &BunResult{result: result}, err
@@ -1670,6 +1675,7 @@ func (b *BunDeleteQuery) Exec(ctx context.Context) (res common.Result, err error
 		// Log SQL string for debugging
 		sqlStr := b.query.String()
 		logger.Error("BunDeleteQuery.Exec failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(b.metricsEnabled, "DELETE", b.schema, b.entity, b.tableName, startedAt, err)
 	return &BunResult{result: result}, err

pkg/common/adapters/database/gorm.go

@@ -583,6 +583,7 @@ func (g *GormSelectQuery) Scan(ctx context.Context, dest interface{}) (err error
 			return tx.Find(dest)
 		})
 		logger.Error("GormSelectQuery.Scan failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "SELECT", g.schema, g.entity, g.tableName, startedAt, err)
 	return err
@@ -613,6 +614,7 @@ func (g *GormSelectQuery) ScanModel(ctx context.Context) (err error) {
 			return tx.Find(g.db.Statement.Model)
 		})
 		logger.Error("GormSelectQuery.ScanModel failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "SELECT", g.schema, g.entity, g.tableName, startedAt, err)
 	return err
@@ -642,6 +644,7 @@ func (g *GormSelectQuery) Count(ctx context.Context) (count int, err error) {
 			return tx.Count(&count64)
 		})
 		logger.Error("GormSelectQuery.Count failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "COUNT", g.schema, g.entity, g.tableName, startedAt, err)
 	return int(count64), err
@@ -671,6 +674,7 @@ func (g *GormSelectQuery) Exists(ctx context.Context) (exists bool, err error) {
 			return tx.Limit(1).Count(&count)
 		})
 		logger.Error("GormSelectQuery.Exists failed. SQL: %s. Error: %v", sqlStr, err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "EXISTS", g.schema, g.entity, g.tableName, startedAt, err)
 	return count > 0, err
@@ -931,6 +935,7 @@ func (g *GormUpdateQuery) Exec(ctx context.Context) (res common.Result, err erro
 			return tx.Updates(g.updates)
 		})
 		logger.Error("GormUpdateQuery.Exec failed. SQL: %s. Error: %v", sqlStr, result.Error)
+		return &GormResult{result: result}, common.WrapSQLError(result.Error, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "UPDATE", g.schema, g.entity, g.tableName, startedAt, result.Error)
 	return &GormResult{result: result}, result.Error
@@ -992,6 +997,7 @@ func (g *GormDeleteQuery) Exec(ctx context.Context) (res common.Result, err erro
 			return tx.Delete(g.model)
 		})
 		logger.Error("GormDeleteQuery.Exec failed. SQL: %s. Error: %v", sqlStr, result.Error)
+		return &GormResult{result: result}, common.WrapSQLError(result.Error, sqlStr)
 	}
 	recordQueryMetrics(g.metricsEnabled, "DELETE", g.schema, g.entity, g.tableName, startedAt, result.Error)
 	return &GormResult{result: result}, result.Error

pkg/common/adapters/database/pgsql.go

@@ -138,7 +138,7 @@ func (p *PgSQLAdapter) Exec(ctx context.Context, query string, args ...interface
 	if err != nil {
 		logger.Error("PgSQL Exec failed: %v", err)
 		recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, err)
-		return nil, err
+		return nil, common.WrapSQLError(err, query)
 	}
 	recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, nil)
 	return &PgSQLResult{result: result}, nil
@@ -164,7 +164,7 @@ func (p *PgSQLAdapter) Query(ctx context.Context, dest interface{}, query string
 	if err != nil {
 		logger.Error("PgSQL Query failed: %v", err)
 		recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, err)
-		return err
+		return common.WrapSQLError(err, query)
 	}
 	defer rows.Close()
 
@@ -511,7 +511,7 @@ func (p *PgSQLSelectQuery) Scan(ctx context.Context, dest interface{}) (err erro
 	if err != nil {
 		logger.Error("PgSQL SELECT failed: %v", err)
 		recordQueryMetrics(p.metricsEnabled, "SELECT", p.schema, p.entity, p.tableName, startedAt, err)
-		return err
+		return common.WrapSQLError(err, query)
 	}
 	defer rows.Close()
 
@@ -534,8 +534,8 @@ func (p *PgSQLSelectQuery) ScanModel(ctx context.Context) error {
 	return p.Scan(ctx, p.model)
 }
 
-// countInternal executes the COUNT query and returns the result without recording metrics.
+// countInternal executes the COUNT query and returns the result and the SQL string without recording metrics.
-func (p *PgSQLSelectQuery) countInternal(ctx context.Context) (int, error) {
+func (p *PgSQLSelectQuery) countInternal(ctx context.Context) (rowCount int, querySQL string, retErr error) {
 	var sb strings.Builder
 	sb.WriteString("SELECT COUNT(*) FROM ")
 	sb.WriteString(p.tableName)
@@ -571,9 +571,9 @@ func (p *PgSQLSelectQuery) countInternal(ctx context.Context) (int, error) {
 
 	var count int
 	if err := row.Scan(&count); err != nil {
-		return 0, err
+		return 0, query, err
 	}
-	return count, nil
+	return count, query, nil
 }
 
 func (p *PgSQLSelectQuery) Count(ctx context.Context) (count int, err error) {
@@ -584,9 +584,11 @@ func (p *PgSQLSelectQuery) Count(ctx context.Context) (count int, err error) {
 		}
 	}()
 	startedAt := time.Now()
-	count, err = p.countInternal(ctx)
+	var sqlStr string
+	count, sqlStr, err = p.countInternal(ctx)
 	if err != nil {
 		logger.Error("PgSQL COUNT failed: %v", err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(p.metricsEnabled, "COUNT", p.schema, p.entity, p.tableName, startedAt, err)
 	return count, err
@@ -600,9 +602,11 @@ func (p *PgSQLSelectQuery) Exists(ctx context.Context) (exists bool, err error)
 		}
 	}()
 	startedAt := time.Now()
-	count, err := p.countInternal(ctx)
+	var sqlStr string
+	count, sqlStr, err := p.countInternal(ctx)
 	if err != nil {
 		logger.Error("PgSQL EXISTS failed: %v", err)
+		err = common.WrapSQLError(err, sqlStr)
 	}
 	recordQueryMetrics(p.metricsEnabled, "EXISTS", p.schema, p.entity, p.tableName, startedAt, err)
 	return count > 0, err
@@ -702,7 +706,7 @@ func (p *PgSQLInsertQuery) Exec(ctx context.Context) (res common.Result, err err
 
 	if err != nil {
 		logger.Error("PgSQL INSERT failed: %v", err)
-		return nil, err
+		return nil, common.WrapSQLError(err, query)
 	}
 
 	return &PgSQLResult{result: result}, nil
@@ -750,7 +754,10 @@ func (p *PgSQLInsertQuery) Scan(ctx context.Context, dest interface{}) (err erro
 		row = p.db.QueryRowContext(ctx, query, args...)
 	}
 
-	return row.Scan(dest)
+	if err := row.Scan(dest); err != nil {
+		return common.WrapSQLError(err, query)
+	}
+	return nil
 }
 
 // PgSQLUpdateQuery implements UpdateQuery for PostgreSQL
@@ -929,7 +936,7 @@ func (p *PgSQLUpdateQuery) Exec(ctx context.Context) (res common.Result, err err
 
 	if err != nil {
 		logger.Error("PgSQL UPDATE failed: %v", err)
-		return nil, err
+		return nil, common.WrapSQLError(err, query)
 	}
 
 	return &PgSQLResult{result: result}, nil
@@ -1007,7 +1014,7 @@ func (p *PgSQLDeleteQuery) Exec(ctx context.Context) (res common.Result, err err
 
 	if err != nil {
 		logger.Error("PgSQL DELETE failed: %v", err)
-		return nil, err
+		return nil, common.WrapSQLError(err, query)
 	}
 
 	return &PgSQLResult{result: result}, nil
@@ -1088,7 +1095,7 @@ func (p *PgSQLTxAdapter) Exec(ctx context.Context, query string, args ...interfa
 	if err != nil {
 		logger.Error("PgSQL Tx Exec failed: %v", err)
 		recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, err)
-		return nil, err
+		return nil, common.WrapSQLError(err, query)
 	}
 	recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, nil)
 	return &PgSQLResult{result: result}, nil
@@ -1102,7 +1109,7 @@ func (p *PgSQLTxAdapter) Query(ctx context.Context, dest interface{}, query stri
 	if err != nil {
 		logger.Error("PgSQL Tx Query failed: %v", err)
 		recordQueryMetrics(p.metricsEnabled, operation, schema, entity, table, startedAt, err)
-		return err
+		return common.WrapSQLError(err, query)
 	}
 	defer rows.Close()
 

pkg/common/recursive_crud.go

@@ -141,8 +141,12 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 			logger.Debug("Skipping insert for %s - no data columns besides _request", tableName)
 		}
 
-	case "update":
+	case "update", "change":
 		// Only perform update if we have data to update
+		if reflection.IsEmptyValue(data[pkName]) {
+			logger.Warn("Skipping update for %s - no primary key", tableName)
+			return result, nil
+		}
 		if hasData {
 			rows, err := p.processUpdate(ctx, regularData, tableName, data[pkName])
 			if err != nil {
@@ -171,10 +175,15 @@ func (p *NestedCUDProcessor) ProcessNestedCUD(
 		}
 
 	case "delete":
+		if reflection.IsEmptyValue(data[pkName]) {
+			logger.Warn("Skipping delete for %s - no primary key", tableName)
+			return result, nil
+		}
+
 		// Process child relations first (for referential integrity)
 		if err := p.processChildRelations(ctx, "delete", data[pkName], relationFields, result.RelationData, modelType, parentIDs); err != nil {
 			logger.Error("Failed to process child relations before delete: table=%s, id=%v, relations=%+v, error=%v", tableName, data[pkName], relationFields, err)
-			return nil, nil
+			return nil, fmt.Errorf("failed to process child relations: %w", err)
 		}
 
 		rows, err := p.processDelete(ctx, tableName, data[pkName])

pkg/common/types.go

@@ -1,5 +1,23 @@
 package common
 
+// SQLError wraps a database error together with the SQL that caused it,
+// so callers can surface the query in API error responses for easier debugging.
+type SQLError struct {
+	Err error
+	SQL string
+}
+
+func (e *SQLError) Error() string { return e.Err.Error() }
+func (e *SQLError) Unwrap() error { return e.Err }
+
+// WrapSQLError wraps err with the given SQL. If err is nil it returns nil.
+func WrapSQLError(err error, sql string) error {
+	if err == nil {
+		return nil
+	}
+	return &SQLError{Err: err, SQL: sql}
+}
+
 type RequestBody struct {
 	Operation string         `json:"operation"`
 	Data      interface{}    `json:"data"`
@@ -104,6 +122,7 @@ type APIError struct {
 	Message string      `json:"message"`
 	Details interface{} `json:"details,omitempty"`
 	Detail  string      `json:"detail,omitempty"`
+	SQL     string      `json:"sql,omitempty"`
 }
 
 type Column struct {

pkg/funcspec/function_api.go

@@ -3,6 +3,7 @@ package funcspec
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -1071,6 +1072,10 @@ func sendError(w http.ResponseWriter, status int, code, message string, err erro
 	}
 	if err != nil {
 		errObj.Detail = err.Error()
+		var sqlErr *common.SQLError
+		if errors.As(err, &sqlErr) {
+			errObj.SQL = sqlErr.SQL
+		}
 	}
 
 	data, _ := json.Marshal(map[string]interface{}{

pkg/reflection/helpers.go

@@ -51,6 +51,31 @@ func ExtractTableNameOnly(fullName string) string {
 	return fullName[startIndex:]
 }
 
+// IsEmptyValue reports whether v is nil, an empty string, or a zero number.
+func IsEmptyValue(v any) bool {
+	if v == nil {
+		return true
+	}
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		if rv.IsNil() {
+			return true
+		}
+		rv = rv.Elem()
+	}
+	switch rv.Kind() {
+	case reflect.String:
+		return rv.String() == ""
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return rv.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return rv.Float() == 0
+	}
+	return false
+}
+
 // GetPointerElement returns the element type if the provided reflect.Type is a pointer.
 // If the type is a slice of pointers, it returns the element type of the pointer within the slice.
 // If neither condition is met, it returns the original type.

pkg/resolvespec/handler.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -1757,18 +1758,21 @@ func (h *Handler) sendResponse(w common.ResponseWriter, data interface{}, metada
 }
 
 func (h *Handler) sendError(w common.ResponseWriter, status int, code, message string, details interface{}) {
+	apiErr := &common.APIError{
+		Code:    code,
+		Message: message,
+		Details: details,
+		Detail:  fmt.Sprintf("%v", details),
+	}
+	if asErr, ok := details.(error); ok {
+		var sqlErr *common.SQLError
+		if errors.As(asErr, &sqlErr) {
+			apiErr.SQL = sqlErr.SQL
+		}
+	}
 	w.SetHeader("Content-Type", "application/json")
 	w.WriteHeader(status)
-	err := w.WriteJSON(common.Response{
+	if err := w.WriteJSON(common.Response{Success: false, Error: apiErr}); err != nil {
-		Success: false,
-		Error: &common.APIError{
-			Code:    code,
-			Message: message,
-			Details: details,
-			Detail:  fmt.Sprintf("%v", details),
-		},
-	})
-	if err != nil {
 		logger.Error("Error sending response: %v", err)
 	}
 }

pkg/restheadspec/empty_result_test.go

@@ -14,23 +14,23 @@ func TestNormalizeResultArray_EmptyArrayWhenNoID(t *testing.T) {
 	handler := &Handler{}
 
 	tests := []struct {
-		name            string
+		name             string
-		input           interface{}
+		input            interface{}
 		shouldBeEmptyObj bool
 	}{
 		{
-			name:            "nil should return empty object",
+			name:             "nil should return empty object",
-			input:           nil,
+			input:            nil,
 			shouldBeEmptyObj: true,
 		},
 		{
-			name:            "empty slice should return empty object",
+			name:             "empty slice should return empty object",
-			input:           []*EmptyTestModel{},
+			input:            []*EmptyTestModel{},
 			shouldBeEmptyObj: true,
 		},
 		{
-			name:            "single element should return the element",
+			name:             "single element should return the element",
-			input:           []*EmptyTestModel{{ID: 1, Name: "test"}},
+			input:            []*EmptyTestModel{{ID: 1, Name: "test"}},
 			shouldBeEmptyObj: false,
 		},
 		{
@@ -138,9 +138,9 @@ func TestSendResponseWithOptions_NoDataFoundHeader(t *testing.T) {
 		t.Errorf("Expected X-No-Data-Found header to be 'true', got '%s'", mockWriter.headers["X-No-Data-Found"])
 	}
 
-	// Check status code is 204 when no records found
+	// Check status code is 200 even when no records found
-	if mockWriter.statusCode != 204 {
+	if mockWriter.statusCode != 200 {
-		t.Errorf("Expected status code 204, got %d", mockWriter.statusCode)
+		t.Errorf("Expected status code 200, got %d", mockWriter.statusCode)
 	}
 
 	// Verify the body is an empty array (list request, SingleRecordAsObject not set)

pkg/restheadspec/handler.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -579,8 +580,8 @@ func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, id st
 	// preload LEFT JOIN (to prevent "table name specified more than once" errors).
 	if len(options.CustomSQLJoin) > 0 {
 		preloadAliasSet := make(map[string]bool, len(options.Preload))
-		for _, p := range options.Preload {
+		for i := range options.Preload {
-			if alias := common.RelationPathToBunAlias(p.Relation); alias != "" {
+			if alias := common.RelationPathToBunAlias(options.Preload[i].Relation); alias != "" {
 				preloadAliasSet[alias] = true
 			}
 		}
@@ -619,16 +620,19 @@ func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, id st
 		logger.Debug("FetchRowNumber: Row number %d for PK %s = %s", rowNum, pkName, fetchRowNumberPKValue)
 
 		// Now filter the main query to this specific primary key
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), fetchRowNumberPKValue)
+		tableAlias := reflection.ExtractTableNameOnly(tableName)
+		query = query.Where(fmt.Sprintf("%s.%s = ?", common.QuoteIdent(tableAlias), common.QuoteIdent(pkName)), fetchRowNumberPKValue)
 	} else if id != "" {
 		// If ID is provided (and not FetchRowNumber), filter by ID
 		pkName := reflection.GetPrimaryKeyName(model)
 		logger.Debug("Filtering by ID=%s: %s", pkName, id)
 
-		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), id)
+		tableAlias := reflection.ExtractTableNameOnly(tableName)
+		query = query.Where(fmt.Sprintf("%s.%s = ?", common.QuoteIdent(tableAlias), common.QuoteIdent(pkName)), id)
 	}
 
 	// Apply sorting
+	tableAlias := reflection.ExtractTableNameOnly(tableName)
 	for _, sort := range options.Sort {
 		direction := "ASC"
 		if strings.EqualFold(sort.Direction, "desc") {
@@ -640,9 +644,12 @@ func (h *Handler) handleRead(ctx context.Context, w common.ResponseWriter, id st
 		if strings.HasPrefix(sort.Column, "(") && strings.HasSuffix(sort.Column, ")") {
 			// For expressions, pass as raw SQL to prevent auto-quoting
 			query = query.OrderExpr(fmt.Sprintf("%s %s", sort.Column, direction))
+		} else if strings.Contains(sort.Column, ".") {
+			// Already qualified (e.g. alias.column) - pass as raw expression to preserve the dot
+			query = query.OrderExpr(fmt.Sprintf("%s %s", sort.Column, direction))
 		} else {
-			// Regular column - let Bun handle quoting
+			// Unqualified column - prefix with main table alias to avoid ambiguity on JOINs
-			query = query.Order(fmt.Sprintf("%s %s", sort.Column, direction))
+			query = query.OrderExpr(fmt.Sprintf("%s.%s %s", common.QuoteIdent(tableAlias), common.QuoteIdent(sort.Column), direction))
 		}
 	}
 
@@ -1360,7 +1367,7 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 
 		// First, read the existing record from the database
 		existingRecord := reflect.New(reflection.GetPointerElement(reflect.TypeOf(model))).Interface()
-		selectQuery := tx.NewSelect().Model(existingRecord).Column("*").Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), targetID)
+		selectQuery := tx.NewSelect().Model(existingRecord).Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), targetID)
 		if err := selectQuery.ScanModel(ctx); err != nil {
 			if err == sql.ErrNoRows {
 				return fmt.Errorf("record not found with ID: %v", targetID)
@@ -2507,11 +2514,7 @@ func (h *Handler) sendResponseWithOptions(w common.ResponseWriter, data interfac
 		data = h.normalizeResultArray(data)
 	}
 
-	if dataLen == 0 {
+	w.WriteHeader(http.StatusOK)
-		w.WriteHeader(http.StatusNoContent)
-	} else {
-		w.WriteHeader(http.StatusOK)
-	}
 
 	if err := w.WriteJSON(data); err != nil {
 		logger.Error("Failed to write JSON response: %v", err)
@@ -2565,10 +2568,8 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 	dataLen := reflection.Len(data)
 
 	// Add X-No-Data-Found header when no records were found
-	httpStatus := http.StatusOK
 	if dataLen == 0 {
 		w.SetHeader("X-No-Data-Found", "true")
-		httpStatus = http.StatusNoContent
 	}
 
 	// Apply normalization after header is set
@@ -2592,7 +2593,7 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 	switch options.ResponseFormat {
 	case "simple":
 		// Simple format: just return the data array
-		w.WriteHeader(httpStatus)
+		w.WriteHeader(http.StatusOK)
 		if err := w.WriteJSON(data); err != nil {
 			logger.Error("Failed to write JSON response: %v", err)
 		}
@@ -2604,7 +2605,7 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 		if metadata != nil {
 			response["count"] = metadata.Total
 		}
-		w.WriteHeader(httpStatus)
+		w.WriteHeader(http.StatusOK)
 		if err := w.WriteJSON(response); err != nil {
 			logger.Error("Failed to write JSON response: %v", err)
 		}
@@ -2615,7 +2616,7 @@ func (h *Handler) sendFormattedResponse(w common.ResponseWriter, data interface{
 			Data:     data,
 			Metadata: metadata,
 		}
-		w.WriteHeader(httpStatus)
+		w.WriteHeader(http.StatusOK)
 		if err := w.WriteJSON(response); err != nil {
 			logger.Error("Failed to write JSON response: %v", err)
 		}
@@ -2645,6 +2646,12 @@ func (h *Handler) sendError(w common.ResponseWriter, statusCode int, code, messa
 		"_error":  errorMsg,
 		"_retval": 1,
 	}
+
+	var sqlErr *common.SQLError
+	if errors.As(err, &sqlErr) {
+		response["_sql"] = sqlErr.SQL
+	}
+
 	w.SetHeader("Content-Type", "application/json")
 	w.WriteHeader(statusCode)
 	if jsonErr := w.WriteJSON(response); jsonErr != nil {

pkg/security/chain.go

@@ -0,0 +1,41 @@
+package security
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+)
+
+// ChainAuthenticator tries each authenticator in order, returning the first success.
+// Login and Logout are delegated to the primary authenticator.
+type ChainAuthenticator struct {
+	authenticators []Authenticator
+}
+
+// NewChainAuthenticator creates a ChainAuthenticator from the given authenticators.
+// At least one authenticator is required; the first is treated as primary for Login/Logout.
+func NewChainAuthenticator(primary Authenticator, rest ...Authenticator) *ChainAuthenticator {
+	return &ChainAuthenticator{
+		authenticators: append([]Authenticator{primary}, rest...),
+	}
+}
+
+func (c *ChainAuthenticator) Authenticate(r *http.Request) (*UserContext, error) {
+	var lastErr error
+	for _, a := range c.authenticators {
+		if uc, err := a.Authenticate(r); err == nil {
+			return uc, nil
+		} else {
+			lastErr = err
+		}
+	}
+	return nil, fmt.Errorf("all authenticators failed; last error: %w", lastErr)
+}
+
+func (c *ChainAuthenticator) Login(ctx context.Context, req LoginRequest) (*LoginResponse, error) {
+	return c.authenticators[0].Login(ctx, req)
+}
+
+func (c *ChainAuthenticator) Logout(ctx context.Context, req LogoutRequest) error {
+	return c.authenticators[0].Logout(ctx, req)
+}

pkg/security/chain_test.go

@@ -0,0 +1,117 @@
+package security
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+// stubAuthenticator is a configurable Authenticator for testing.
+type stubAuthenticator struct {
+	userCtx *UserContext
+	err     error
+}
+
+func (s *stubAuthenticator) Authenticate(_ *http.Request) (*UserContext, error) {
+	return s.userCtx, s.err
+}
+
+func (s *stubAuthenticator) Login(_ context.Context, _ LoginRequest) (*LoginResponse, error) {
+	if s.err != nil {
+		return nil, s.err
+	}
+	return &LoginResponse{Token: "tok"}, nil
+}
+
+func (s *stubAuthenticator) Logout(_ context.Context, _ LogoutRequest) error {
+	return s.err
+}
+
+func TestChainAuthenticator_Authenticate(t *testing.T) {
+	successCtx := &UserContext{UserID: 42, UserName: "alice"}
+	failStub := &stubAuthenticator{err: fmt.Errorf("no token")}
+	okStub := &stubAuthenticator{userCtx: successCtx}
+
+	t.Run("primary succeeds", func(t *testing.T) {
+		chain := NewChainAuthenticator(okStub, failStub)
+		req := httptest.NewRequest("GET", "/", nil)
+
+		uc, err := chain.Authenticate(req)
+		if err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+		if uc.UserID != 42 {
+			t.Errorf("expected UserID 42, got %d", uc.UserID)
+		}
+	})
+
+	t.Run("primary fails, secondary succeeds", func(t *testing.T) {
+		chain := NewChainAuthenticator(failStub, okStub)
+		req := httptest.NewRequest("GET", "/", nil)
+
+		uc, err := chain.Authenticate(req)
+		if err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+		if uc.UserID != 42 {
+			t.Errorf("expected UserID 42, got %d", uc.UserID)
+		}
+	})
+
+	t.Run("all fail", func(t *testing.T) {
+		chain := NewChainAuthenticator(failStub, failStub)
+		req := httptest.NewRequest("GET", "/", nil)
+
+		_, err := chain.Authenticate(req)
+		if err == nil {
+			t.Fatal("expected error when all authenticators fail")
+		}
+	})
+
+	t.Run("three in chain, first two fail", func(t *testing.T) {
+		chain := NewChainAuthenticator(failStub, failStub, okStub)
+		req := httptest.NewRequest("GET", "/", nil)
+
+		uc, err := chain.Authenticate(req)
+		if err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+		if uc.UserName != "alice" {
+			t.Errorf("expected UserName alice, got %s", uc.UserName)
+		}
+	})
+}
+
+func TestChainAuthenticator_LoginLogout(t *testing.T) {
+	primary := &stubAuthenticator{userCtx: &UserContext{UserID: 1}}
+	secondary := &stubAuthenticator{userCtx: &UserContext{UserID: 2}}
+	chain := NewChainAuthenticator(primary, secondary)
+	ctx := context.Background()
+
+	t.Run("login delegates to primary", func(t *testing.T) {
+		resp, err := chain.Login(ctx, LoginRequest{Username: "u", Password: "p"})
+		if err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+		if resp.Token != "tok" {
+			t.Errorf("expected token from primary, got %s", resp.Token)
+		}
+	})
+
+	t.Run("logout delegates to primary", func(t *testing.T) {
+		if err := chain.Logout(ctx, LogoutRequest{}); err != nil {
+			t.Fatalf("expected no error, got %v", err)
+		}
+	})
+
+	t.Run("login error from primary is returned", func(t *testing.T) {
+		failPrimary := &stubAuthenticator{err: fmt.Errorf("db down")}
+		chain2 := NewChainAuthenticator(failPrimary, secondary)
+		_, err := chain2.Login(ctx, LoginRequest{})
+		if err == nil {
+			t.Fatal("expected error from primary login failure")
+		}
+	})
+}

pkg/websocketspec/handler.go

@@ -3,6 +3,7 @@ package websocketspec
 import (
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -17,6 +18,17 @@ import (
 	"github.com/bitechdev/ResolveSpec/pkg/reflection"
 )
 
+// newErrorResponseFromErr creates an error response from a Go error, including the SQL
+// query in the error info when the error is a database SQLError.
+func newErrorResponseFromErr(id, code string, err error) *ResponseMessage {
+	resp := NewErrorResponse(id, code, err.Error())
+	var sqlErr *common.SQLError
+	if errors.As(err, &sqlErr) {
+		resp.Error.SQL = sqlErr.SQL
+	}
+	return resp
+}
+
 // Handler handles WebSocket connections and messages
 type Handler struct {
 	db                  common.Database
@@ -236,7 +248,7 @@ func (h *Handler) handleRead(conn *Connection, msg *Message, hookCtx *HookContex
 
 	if err != nil {
 		logger.Error("[WebSocketSpec] Read operation failed: %v", err)
-		errResp := NewErrorResponse(msg.ID, "read_error", err.Error())
+		errResp := newErrorResponseFromErr(msg.ID, "read_error", err)
 		_ = conn.SendJSON(errResp)
 		return
 	}
@@ -272,7 +284,7 @@ func (h *Handler) handleCreate(conn *Connection, msg *Message, hookCtx *HookCont
 	data, err := h.create(hookCtx)
 	if err != nil {
 		logger.Error("[WebSocketSpec] Create operation failed: %v", err)
-		errResp := NewErrorResponse(msg.ID, "create_error", err.Error())
+		errResp := newErrorResponseFromErr(msg.ID, "create_error", err)
 		_ = conn.SendJSON(errResp)
 		return
 	}
@@ -310,7 +322,7 @@ func (h *Handler) handleUpdate(conn *Connection, msg *Message, hookCtx *HookCont
 	data, err := h.update(hookCtx)
 	if err != nil {
 		logger.Error("[WebSocketSpec] Update operation failed: %v", err)
-		errResp := NewErrorResponse(msg.ID, "update_error", err.Error())
+		errResp := newErrorResponseFromErr(msg.ID, "update_error", err)
 		_ = conn.SendJSON(errResp)
 		return
 	}
@@ -348,7 +360,7 @@ func (h *Handler) handleDelete(conn *Connection, msg *Message, hookCtx *HookCont
 	err := h.delete(hookCtx)
 	if err != nil {
 		logger.Error("[WebSocketSpec] Delete operation failed: %v", err)
-		errResp := NewErrorResponse(msg.ID, "delete_error", err.Error())
+		errResp := newErrorResponseFromErr(msg.ID, "delete_error", err)
 		_ = conn.SendJSON(errResp)
 		return
 	}

pkg/websocketspec/message.go

@@ -99,6 +99,9 @@ type ErrorInfo struct {
 
 	// Details contains additional error context
 	Details map[string]interface{} `json:"details,omitempty"`
+
+	// SQL is the query that caused the error, populated for database errors
+	SQL string `json:"sql,omitempty"`
 }
 
 // RequestMessage represents a client request