How to Find Foreign Key References and Their Populated Values in a Database?

Finding Foreign Key References and Populated Values

In a database schema, it's common to have tables that reference other tables through foreign keys. To identify tables with foreign keys referencing a specific table and column, as well as tables where these foreign keys contain data, the following query can be utilized:

This query retrieves information from the KEY_COLUMN_USAGE table in the information_schema database, which contains metadata about foreign key relationships. By filtering the results on the specified REFERENCED_TABLE_NAME (X) and REFERENCED_COLUMN_NAME (X_id), the query lists all tables that have foreign keys pointing to the X table's X_id column.

Additionally, to ensure that only tables with populated foreign keys are included, the query can be expanded to include a check for non-null values in the foreign key column:

This updated query retrieves the table name along with the foreign key metadata, ensuring that only tables with populated foreign keys are included in the results. By sorting the results by table name, the output provides a clear view of which tables have foreign key references to the specified table and column, and which of those tables contain data in the foreign key field.

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