Method LoadType

conn.go:1290–1362

LoadType inspects the database for typeName and produces a [pgtype.Type] suitable for registration. typeName must be the name of a type where the underlying type(s) is already understood by pgx. It is for derived types. In particular, typeName must be one of the following: - An array type name of a

(ctx context.Context, typeName string)

//   - A range type name where the element type is already registered.
//   - A multirange type name where the element type is already registered.
func (c *Conn) LoadType(ctx context.Context, typeName string) (*pgtype.Type, error) {
	var oid uint32

	err := c.QueryRow(ctx, "select $1::text::regtype::oid;", typeName).Scan(&oid)
	if err != nil {
		return nil, err
	}

	var typtype string
	var typbasetype uint32

	err = c.QueryRow(ctx, "select typtype::text, typbasetype from pg_type where oid=$1", oid).Scan(&typtype, &typbasetype)
	if err != nil {
		return nil, err
	}

	switch typtype {
	case "b": // array
		elementOID, err := c.getArrayElementOID(ctx, oid)
		if err != nil {
			return nil, err
		}

		dt, ok := c.TypeMap().TypeForOID(elementOID)
		if !ok {
			return nil, errors.New("array element OID not registered")
		}

		return &pgtype.Type{Name: typeName, OID: oid, Codec: &pgtype.ArrayCodec{ElementType: dt}}, nil
	case "c": // composite
		fields, err := c.getCompositeFields(ctx, oid)
		if err != nil {
			return nil, err
		}

		return &pgtype.Type{Name: typeName, OID: oid, Codec: &pgtype.CompositeCodec{Fields: fields}}, nil
	case "d": // domain
		dt, ok := c.TypeMap().TypeForOID(typbasetype)
		if !ok {
			return nil, errors.New("domain base type OID not registered")
		}

		return &pgtype.Type{Name: typeName, OID: oid, Codec: dt.Codec}, nil
	case "e": // enum
		return &pgtype.Type{Name: typeName, OID: oid, Codec: &pgtype.EnumCodec{}}, nil
	case "r": // range
		elementOID, err := c.getRangeElementOID(ctx, oid)
		if err != nil {
			return nil, err
		}

		dt, ok := c.TypeMap().TypeForOID(elementOID)
		if !ok {
			return nil, errors.New("range element OID not registered")
		}

		return &pgtype.Type{Name: typeName, OID: oid, Codec: &pgtype.RangeCodec{ElementType: dt}}, nil
	case "m": // multirange