How to find all the dependencies of a table in SQL Server

This is particularly important when performing database maintenance, such as altering or dropping a table.

Here’s a guide to finding all the dependencies of a table in SQL Server, including child tables that refer to the parent table.

Method 1: Using sp_depends

SQL Server provides a system stored procedure called sp_depends that helps identify dependencies related to a specific object, such as a table. This includes views, stored procedures, and functions that rely on the table.

Syntax:

sp_depends 'dbo.TableName';

Example:

sp_depends 'dbo.MyTable';

This will return a list of objects that depend on the dbo.MyTable table.

While sp_depends is simple to use, it has limitations.

For example, it might not catch dependencies that involve dynamic SQL or those created after a table’s creation. For a more thorough search, you may want to explore additional methods.

Method 2: Using information_schema.routines

The information_schema views provide a more flexible and comprehensive way of searching for dependencies, especially in routines (such as stored procedures or functions). You can search through the routines view to find references to a specific table in the SQL code of stored procedures and functions.

Syntax:

SELECT *
FROM information_schema.routines ISR
WHERE CHARINDEX('dbo.TableName', ISR.ROUTINE_DEFINITION) > 0;

Example:

SELECT *
FROM information_schema.routines ISR
WHERE CHARINDEX('dbo.MyTable', ISR.ROUTINE_DEFINITION) > 0

This query checks the SQL definition of stored procedures and functions for references to the dbo.MyTable table. It will return any routines that include dbo.MyTable in their code.

Method 3: Using Dynamic Management View (sys.dm_sql_referencing_entities)

SQL Server provides a dynamic management view (DMV) called sys.dm_sql_referencing_entities that returns the entities that reference a specified object. This method is useful because it directly lists the objects referencing a given table.

Syntax:

SELECT referencing_schema_name, referencing_entity_name,
       referencing_id, referencing_class_desc, is_caller_dependent
FROM sys.dm_sql_referencing_entities ('dbo.TableName', 'OBJECT')

Example:

SELECT referencing_schema_name, referencing_entity_name,
       referencing_id, referencing_class_desc, is_caller_dependent
FROM sys.dm_sql_referencing_entities ('dbo.MyTable', 'OBJECT')

This query provides detailed information about the entities (such as views, procedures, and other tables) that reference the dbo.MyTable table. It also indicates whether the reference is dependent on the caller.

By using the methods above, you can get a comprehensive view of the relationships between your database objects.