fix: Fix bug

Author: lighttiger2505

internal/database/cache.go

@@ -27,6 +27,14 @@ func (u *DBCacheGenerator) GenerateDBCachePrimary(ctx context.Context) (*DBCache
 	if err != nil {
 		return nil, err
 	}
+	if dbCache.defaultSchema == "" {
+		var topKey string
+		for k, _ := range dbCache.Schemas {
+			topKey = k
+			continue
+		}
+		dbCache.defaultSchema = dbCache.Schemas[topKey]
+	}
 	dbCache.SchemaTables, err = u.repo.SchemaTables(ctx)
 	if err != nil {
 		return nil, err

internal/database/postgresql.go

@@ -127,11 +127,14 @@ func (db *PostgreSQLDBRepository) Databases(ctx context.Context) ([]string, erro
 
 func (db *PostgreSQLDBRepository) CurrentSchema(ctx context.Context) (string, error) {
 	row := db.Conn.QueryRowContext(ctx, "SELECT current_schema()")
-	var database string
+	var database sql.NullString
 	if err := row.Scan(&database); err != nil {
 		return "", err
 	}
-	return database, nil
+	if database.Valid {
+		return database.String, nil
+	}
+	return "", nil
 }
 
 func (db *PostgreSQLDBRepository) Schemas(ctx context.Context) ([]string, error) {