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
2026-05-19 19:26:09 +02:00
parent 80fb49bc5e
commit cb735f0754
6 changed files with 430 additions and 147 deletions
@@ -0,0 +1,152 @@
+package sqlite
+
+import "strings"
+
+// SQLiteToCanonicalTypes maps SQLite type names to canonical types.
+// SQLite has type affinity rules; this maps common type names including
+// MySQL/PostgreSQL types that users write in SQLite schemas.
+var SQLiteToCanonicalTypes = map[string]string{
+	// Integer affinity
+	"integer":          "int",
+	"int":              "int",
+	"tinyint":          "int8",
+	"smallint":         "int16",
+	"mediumint":        "int",
+	"bigint":           "int64",
+	"unsigned big int": "uint64",
+	"int2":             "int16",
+	"int8":             "int64",
+	// Real affinity
+	"real":             "float64",
+	"double":           "float64",
+	"double precision": "float64",
+	"float":            "float32",
+	// Numeric affinity
+	"numeric": "decimal",
+	"decimal": "decimal",
+	// Boolean (stored as integer in SQLite)
+	"boolean": "bool",
+	"bool":    "bool",
+	// Date/time (stored as text in SQLite)
+	"date":      "date",
+	"datetime":  "timestamp",
+	"timestamp": "timestamp",
+	// Text affinity
+	"text":              "string",
+	"varchar":           "string",
+	"char":              "string",
+	"character":         "string",
+	"varying character": "string",
+	"nchar":             "string",
+	"nvarchar":          "string",
+	"clob":              "text",
+	// Blob affinity
+	"blob": "bytea",
+}
+
+// CanonicalToSQLiteAffinity maps type names to SQLite type affinity names.
+// Accepts both Go canonical names ("int", "string") and SQL canonical names
+// ("integer", "varchar") so the writer handles input from any reader.
+// The five SQLite type affinities are TEXT, INTEGER, REAL, NUMERIC, BLOB.
+var CanonicalToSQLiteAffinity = map[string]string{
+	// INTEGER affinity — Go canonical
+	"int":    "INTEGER",
+	"int8":   "INTEGER",
+	"int16":  "INTEGER",
+	"int32":  "INTEGER",
+	"int64":  "INTEGER",
+	"uint":   "INTEGER",
+	"uint8":  "INTEGER",
+	"uint16": "INTEGER",
+	"uint32": "INTEGER",
+	"uint64": "INTEGER",
+	"bool":   "INTEGER",
+	// INTEGER affinity — SQL canonical
+	"integer":     "INTEGER",
+	"smallint":    "INTEGER",
+	"bigint":      "INTEGER",
+	"serial":      "INTEGER",
+	"smallserial": "INTEGER",
+	"bigserial":   "INTEGER",
+	"boolean":     "INTEGER",
+	"tinyint":     "INTEGER",
+	"mediumint":   "INTEGER",
+	// REAL affinity — Go canonical
+	"float32": "REAL",
+	"float64": "REAL",
+	// REAL affinity — SQL canonical
+	"real":             "REAL",
+	"float":            "REAL",
+	"double":           "REAL",
+	"double precision": "REAL",
+	// NUMERIC affinity
+	"decimal":    "NUMERIC",
+	"numeric":    "NUMERIC",
+	"money":      "NUMERIC",
+	"smallmoney": "NUMERIC",
+	// BLOB affinity
+	"bytea": "BLOB",
+	"blob":  "BLOB",
+	// TEXT affinity — Go canonical
+	"string": "TEXT",
+	"text":   "TEXT",
+	// TEXT affinity — SQL canonical
+	"varchar":     "TEXT",
+	"char":        "TEXT",
+	"nvarchar":    "TEXT",
+	"nchar":       "TEXT",
+	"citext":      "TEXT",
+	"date":        "TEXT",
+	"time":        "TEXT",
+	"timetz":      "TEXT",
+	"timestamp":   "TEXT",
+	"timestamptz": "TEXT",
+	"datetime":    "TEXT",
+	"uuid":        "TEXT",
+	"json":        "TEXT",
+	"jsonb":       "TEXT",
+	"xml":         "TEXT",
+	"inet":        "TEXT",
+	"cidr":        "TEXT",
+	"macaddr":     "TEXT",
+}
+
+// ConvertSQLiteToCanonical converts a SQLite type name to the canonical type.
+// Strips dimension parameters (e.g. VARCHAR(255) → string) and handles
+// SQLite's flexible affinity rules. Defaults to "string" for unknown types.
+func ConvertSQLiteToCanonical(sqliteType string) string {
+	base := strings.ToUpper(strings.TrimSpace(sqliteType))
+	if idx := strings.Index(base, "("); idx >= 0 {
+		base = strings.TrimSpace(base[:idx])
+	}
+	lower := strings.ToLower(base)
+
+	if canonical, ok := SQLiteToCanonicalTypes[lower]; ok {
+		return canonical
+	}
+
+	// Prefix match for types like "VARYING CHARACTER(255)"
+	for key, canonical := range SQLiteToCanonicalTypes {
+		if strings.HasPrefix(lower, key) {
+			return canonical
+		}
+	}
+
+	return "string"
+}
+
+// ConvertCanonicalToSQLite converts a canonical type (or any SQL type) to its
+// SQLite type affinity. Defaults to TEXT for unrecognised types.
+func ConvertCanonicalToSQLite(canonicalType string) string {
+	normalized := strings.ToLower(strings.TrimSpace(canonicalType))
+	if idx := strings.Index(normalized, "("); idx >= 0 {
+		normalized = strings.TrimSpace(normalized[:idx])
+	}
+	normalized = strings.TrimSuffix(normalized, "[]")
+
+	if affinity, ok := CanonicalToSQLiteAffinity[normalized]; ok {
+		return affinity
+	}
+
+	return "TEXT"
+}