feat(sqlite): add SQLite type mapping and conversion functions

* Implement SQLiteToCanonicalTypes for type mapping
* Add ConvertSQLiteToCanonical and ConvertCanonicalToSQLite functions
* Update mapDataType to utilize new conversion logic

pkg/mssql/datatypes.go

@@ -2,32 +2,73 @@ package mssql
 
 import "strings"
 
-// CanonicalToMSSQLTypes maps canonical types to MSSQL types
+// CanonicalToMSSQLTypes maps canonical types to MSSQL types.
+// Accepts both Go canonical names ("int", "string") and SQL canonical names
+// ("integer", "varchar") so the writer handles input from any reader.
 var CanonicalToMSSQLTypes = map[string]string{
-	"bool":        "BIT",
-	"int8":        "TINYINT",
-	"int16":       "SMALLINT",
-	"int":         "INT",
-	"int32":       "INT",
-	"int64":       "BIGINT",
-	"uint":        "BIGINT",
-	"uint8":       "SMALLINT",
-	"uint16":      "INT",
-	"uint32":      "BIGINT",
-	"uint64":      "BIGINT",
-	"float32":     "REAL",
-	"float64":     "FLOAT",
-	"decimal":     "NUMERIC",
-	"string":      "NVARCHAR(255)",
-	"text":        "NVARCHAR(MAX)",
+	// Boolean — Go and SQL canonical
+	"bool":    "BIT",
+	"boolean": "BIT",
+	// Integer — Go canonical
+	"int8":   "TINYINT",
+	"int16":  "SMALLINT",
+	"int":    "INT",
+	"int32":  "INT",
+	"int64":  "BIGINT",
+	"uint":   "BIGINT",
+	"uint8":  "TINYINT",
+	"uint16": "SMALLINT",
+	"uint32": "BIGINT",
+	"uint64": "BIGINT",
+	// Integer — SQL canonical (serial types map to base integer; IDENTITY is set via AutoIncrement)
+	"integer":      "INT",
+	"smallint":     "SMALLINT",
+	"bigint":       "BIGINT",
+	"tinyint":      "TINYINT",
+	"serial":       "INT",
+	"smallserial":  "SMALLINT",
+	"bigserial":    "BIGINT",
+	// Float — Go canonical
+	"float32": "REAL",
+	"float64": "FLOAT",
+	// Float — SQL canonical
+	"real":             "REAL",
+	"double precision": "FLOAT",
+	"double":           "FLOAT",
+	// Decimal/numeric
+	"decimal": "NUMERIC",
+	"numeric": "NUMERIC",
+	"money":   "MONEY",
+	// String — Go canonical
+	"string": "NVARCHAR(255)",
+	"text":   "NVARCHAR(MAX)",
+	// String — SQL canonical
+	"varchar":  "NVARCHAR(255)",
+	"char":     "NCHAR",
+	"nvarchar": "NVARCHAR(255)",
+	"nchar":    "NCHAR",
+	"citext":   "NVARCHAR(MAX)",
+	// Date/time
 	"date":        "DATE",
 	"time":        "TIME",
+	"timetz":      "DATETIMEOFFSET",
 	"timestamp":   "DATETIME2",
 	"timestamptz": "DATETIMEOFFSET",
-	"uuid":        "UNIQUEIDENTIFIER",
-	"json":        "NVARCHAR(MAX)",
-	"jsonb":       "NVARCHAR(MAX)",
-	"bytea":       "VARBINARY(MAX)",
+	"datetime":    "DATETIME2",
+	"interval":    "NVARCHAR(50)",
+	// UUID
+	"uuid": "UNIQUEIDENTIFIER",
+	// JSON — MSSQL has no native JSON type; stored as NVARCHAR(MAX)
+	"json":  "NVARCHAR(MAX)",
+	"jsonb": "NVARCHAR(MAX)",
+	// Binary
+	"bytea": "VARBINARY(MAX)",
+	"blob":  "VARBINARY(MAX)",
+	// Network/geo types — no MSSQL native equivalent
+	"xml":     "XML",
+	"inet":    "NVARCHAR(45)",
+	"cidr":    "NVARCHAR(43)",
+	"macaddr": "NVARCHAR(17)",
 }
 
 // MSSQLToCanonicalTypes maps MSSQL types to canonical types
@@ -68,47 +109,50 @@ var MSSQLToCanonicalTypes = map[string]string{
 	"geometry":         "string",
 }
 
-// ConvertCanonicalToMSSQL converts a canonical type to MSSQL type
+// MSSQLTypeSynonyms maps MSSQL type aliases to their canonical MSSQL name.
+var MSSQLTypeSynonyms = map[string]string{
+	"integer":  "int",
+	"dec":      "decimal",
+	"float(n)": "float",
+}
+
+// NormalizeMSSQLType maps an MSSQL base type (no dimension parameters) to its
+// canonical MSSQL form. Unknown types are returned as-is (lowercased).
+func NormalizeMSSQLType(baseType string) string {
+	lower := strings.ToLower(strings.TrimSpace(baseType))
+	if canonical, ok := MSSQLTypeSynonyms[lower]; ok {
+		return canonical
+	}
+	return lower
+}
+
+// ConvertCanonicalToMSSQL converts a canonical type (Go or SQL) to an MSSQL type.
+// Strips dimension parameters before lookup. Defaults to NVARCHAR(255) for unknown types.
 func ConvertCanonicalToMSSQL(canonicalType string) string {
-	// Check direct mapping
-	if mssqlType, exists := CanonicalToMSSQLTypes[strings.ToLower(canonicalType)]; exists {
+	base := strings.ToLower(strings.TrimSpace(canonicalType))
+	if idx := strings.Index(base, "("); idx >= 0 {
+		base = strings.TrimSpace(base[:idx])
+	}
+	base = strings.TrimSuffix(base, "[]")
+
+	if mssqlType, exists := CanonicalToMSSQLTypes[base]; exists {
 		return mssqlType
 	}
 
-	// Try to find by prefix
-	lowerType := strings.ToLower(canonicalType)
-	for canonical, mssql := range CanonicalToMSSQLTypes {
-		if strings.HasPrefix(lowerType, canonical) {
-			return mssql
-		}
-	}
-
-	// Default to NVARCHAR
 	return "NVARCHAR(255)"
 }
 
-// ConvertMSSQLToCanonical converts an MSSQL type to canonical type
+// ConvertMSSQLToCanonical converts an MSSQL type to the canonical type.
+// Strips dimension parameters before lookup. Defaults to "string" for unknown types.
 func ConvertMSSQLToCanonical(mssqlType string) string {
-	// Extract base type (remove parentheses and parameters)
-	baseType := mssqlType
-	if idx := strings.Index(baseType, "("); idx != -1 {
-		baseType = baseType[:idx]
+	base := strings.ToLower(strings.TrimSpace(mssqlType))
+	if idx := strings.Index(base, "("); idx >= 0 {
+		base = strings.TrimSpace(base[:idx])
 	}
-	baseType = strings.TrimSpace(baseType)
 
-	// Check direct mapping
-	if canonicalType, exists := MSSQLToCanonicalTypes[strings.ToLower(baseType)]; exists {
+	if canonicalType, exists := MSSQLToCanonicalTypes[base]; exists {
 		return canonicalType
 	}
 
-	// Try to find by prefix
-	lowerType := strings.ToLower(baseType)
-	for mssql, canonical := range MSSQLToCanonicalTypes {
-		if strings.HasPrefix(lowerType, mssql) {
-			return canonical
-		}
-	}
-
-	// Default to string
 	return "string"
 }