How to use the piicatcher.explorer.databases.RelDbExplorer function in piicatcher

    @classmethod
    def factory(cls, ns):
        logging.debug("Relational Db Factory entered")
        explorer = None
        if ns.connection_type == "mysql":
            explorer = MySQLExplorer(ns)
        elif ns.connection_type == "postgres" or ns.connection_type == "redshift":
            explorer = PostgreSQLExplorer(ns)
        elif ns.connection_type == "oracle":
            explorer = OracleExplorer(ns)
        assert explorer is not None

        return explorer


class MySQLExplorer(RelDbExplorer):
    _catalog_query = """
        SELECT
            TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, DATA_TYPE
        FROM
            INFORMATION_SCHEMA.COLUMNS
        WHERE
            TABLE_SCHEMA NOT IN ('information_schema', 'performance_schema', 'sys', 'mysql')
            AND DATA_TYPE RLIKE 'char.*|varchar.*|text'
        ORDER BY table_schema, table_name, column_name
    """

    _sample_query_template = (
        "select {column_list} from {schema_name}.{table_name} limit 10"
    )

    def __init__(self, ns):

def _get_catalog_query(self):
        return self._catalog_query

    @classmethod
    def _get_sample_query(cls, schema_name, table_name, column_list):
        return cls._sample_query_template.format(
            column_list='"{0}"'.format(
                '","'.join(col.get_name() for col in column_list)
            ),
            schema_name=schema_name.get_name(),
            table_name=table_name.get_name(),
        )


class PostgreSQLExplorer(RelDbExplorer):
    _catalog_query = """
        SELECT
            TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, DATA_TYPE
        FROM
            INFORMATION_SCHEMA.COLUMNS
        WHERE
            TABLE_SCHEMA NOT IN ('information_schema', 'pg_catalog')
            AND DATA_TYPE SIMILAR TO '%char%|%text%'
        ORDER BY table_schema, table_name, column_name
    """

    _sample_query_template = "select {column_list} from {schema_name}.{table_name} TABLESAMPLE BERNOULLI (10)"

    def __init__(self, ns):
        super(PostgreSQLExplorer, self).__init__(ns)
        self._pg_database = (

def __init__(self, ns):
        super(RelDbExplorer, self).__init__(ns)
        self.host = ns.host
        self.user = ns.user
        self.password = ns.password
        self.port = (
            int(ns.port)
            if "port" in vars(ns) and ns.port is not None
            else self.default_port
        )

def _get_catalog_query(self):
        return self._catalog_query

    @classmethod
    def _get_sample_query(cls, schema_name, table_name, column_list):
        return cls._sample_query_template.format(
            column_list='"{0}"'.format(
                '","'.join(col.get_name() for col in column_list)
            ),
            schema_name=schema_name.get_name(),
            table_name=table_name.get_name(),
        )


class OracleExplorer(RelDbExplorer):
    _catalog_query = """
        SELECT
            '{db}', TABLE_NAME, COLUMN_NAME
        FROM
            USER_TAB_COLUMNS
        WHERE UPPER(DATA_TYPE) LIKE '%CHAR%'
        ORDER BY TABLE_NAME, COLUMN_ID
    """

    _sample_query_template = "select {column_list} from {table_name} sample(5)"
    _select_query_template = "select {column_list} from {table_name}"
    _count_query = "select count(*) from {table_name}"

    def __init__(self, ns):
        super(OracleExplorer, self).__init__(ns)
        self._oracle_database = ns.database