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link_schema

The LINK_SCHEMA function in H2 database is used to retrieve information about the linked tables in the current schema.

2. Syntax​

The syntax for the LINK_SCHEMA function in H2 database is as follows:

LINK_SCHEMA('schemaPattern', 'tableNamePattern')

Arguments​

  • schemaPattern (optional): The pattern to match the schema names. By default, it matches all schemas.
  • tableNamePattern (optional): The pattern to match the table names. By default, it matches all tables.

Return​

  • The LINK_SCHEMA function returns a result set with the following columns:
    • TABLE_CAT: The catalog name (database name).
    • TABLE_SCHEM: The schema name.
    • TABLE_NAME: The table name.
    • TABLE_TYPE: The type of the table.

3. Notes​

  • The LINK_SCHEMA function in H2 database provides information about linked tables, which are tables defined in other databases or schemas that are linked to the current database.
  • If no arguments are provided, the function returns information about all linked tables in all schemas.
  • The schema and table name patterns can contain wildcard characters like % and _ for pattern matching.

4. Examples​

Here are a few examples demonstrating the usage of the LINK_SCHEMA function in H2 database:

Example 1 - Retrieving information about all linked tables:​

SELECT * FROM LINK_SCHEMA();

Output:

TABLE_CAT | TABLE_SCHEM | TABLE_NAME | TABLE_TYPE
----------+-------------+------------+-----------
mydb      | public      | customers  | TABLE
mydb      | public      | orders     | TABLE

Example 2 - Retrieving information about linked tables in a specific schema:​

SELECT * FROM LINK_SCHEMA('public', '%');

Output:

TABLE_CAT | TABLE_SCHEM | TABLE_NAME | TABLE_TYPE
----------+-------------+------------+-----------
mydb      | public      | customers  | TABLE
mydb      | public      | orders     | TABLE

Example 3 - Retrieving information about a specific linked table:​

SELECT * FROM LINK_SCHEMA('%', 'customers');

Output:

TABLE_CAT | TABLE_SCHEM | TABLE_NAME | TABLE_TYPE
----------+-------------+------------+-----------
mydb      | public      | customers  | TABLE
  • TABLES - Retrieve information about tables in the current database.