def map_to_big_query_data_type(column_type):
    """Converts Postgres column types into BigQuery column types."""
    if (
        column_type.startswith("int")
        or column_type.startswith("bigint")
        or column_type.startswith("smallint")
    ):
        return "INT64"
    if column_type.startswith("bool"):
        return "BOOLEAN"
    if column_type.startswith("double") or column_type.startswith("decimal"):
        return "FLOAT64"
    if (
        column_type.startswith("char")
        or column_type.startswith("text")
        or column_type.startswith("json")
    ):
        return "STRING"
    if column_type.startswith("timestamp"):
        return "TIMESTAMP"
    if column_type.startswith("datetime"):
        return "DATETIME"
    if column_type.startswith("date"):
        return "DATE"
    if column_type.startswith("time"):
        return "TIME"