Query mapping table information

Tablestore SDK for Python queries the field names, field types, and primary key information of a mapping table.

Prerequisites

Install Tablestore SDK for Python and initialize a client.
SQL query requires version 5.4.2 or later. We recommend that you use the latest version.

Description

Call the exe_sql_query method to execute a DESCRIBE statement and query the field names, field types, primary key information, nullability, and other schema information of a mapping table.

def exe_sql_query(self, query)

The following example queries the schema of example_table.

query = "DESCRIBE example_table"
row_list, _, _ = client.exe_sql_query(query)

for row in row_list:
    print(dict(row.attribute_columns))

Parameters

The exe_sql_query method contains the following parameter.

Name	Type	Description
query (required)	String	The `DESCRIBE <mapping_table_name>` statement to execute, where `<mapping_table_name>` is the mapping table name.

Response

The exe_sql_query method returns a tuple that contains the following elements.

Element	Type	Description
`row_list`	List[Row]	A list of mapping table fields. Each `Row` object contains the following result-set fields.
`table_capacity_units`	List[Tuple]	Read and write CUs consumed by data tables. Each tuple contains a table name and a `CapacityUnit` object.
`search_capacity_units`	List[Tuple]	Read and write CUs consumed by search indexes. Each tuple contains a search index name and a `CapacityUnit` object.

Result-set fields

Field	Type	Description
`Field`	String	The field name.
`Type`	String	The SQL field type.
`Null`	String	Whether the field can be null.
`Key`	String	Whether the field is a primary key. A primary key column returns `PRI`.
`Default`	String	The default value.
`Extra`	String	Additional field information.