Demystifying Triggers: How to Find All Triggers and Their Linked Tables in SQL Server

This code retrieves information about all triggers in a SQL Server database, along with the tables they're defined on and the schemas those tables belong to.

Breakdown:

1. SELECT Clause:

   • TBL.name AS TableName: Selects the name of the table the trigger is associated with and aliases it as TableName.
   • Schema_name(TBL.schema_id) AS Table_SchemaName: Uses the Schema_name function to get the schema name of the table and aliases it as Table_SchemaName.
   • TRG.name AS TriggerName: Selects the name of the trigger and aliases it as TriggerName.
   • TRG.parent_class_desc: Selects the type of trigger (e.g., AFTER INSERT, INSTEAD OF DELETE).
   • CASE WHEN TRG.is_disabled = 0 THEN 'Enabled' ELSE 'Disabled' END AS TRG_Status: Uses a CASE expression to determine the trigger's status (Enabled or Disabled) based on the value in the is_disabled column.

2. FROM Clause:

3. INNER JOIN Clause:

Explanation:

• System views like sys.triggers and sys.tables provide metadata about database objects.
• The OBJECT_ID column in sys.tables uniquely identifies a table.
• The parent_id column in sys.triggers references the OBJECT_ID of the table the trigger is defined on.
• The is_disabled column in sys.triggers indicates whether the trigger is enabled (0) or disabled (1).
• The CASE expression provides a more readable representation of the trigger's status.

Additional Notes:

• You might need permissions to access system views in SQL Server.
• This code retrieves information about table-level triggers. To include CLR triggers (triggers written in Common Language Runtime languages), you might need additional queries or tools.

SELECT 
    TBL.name AS TableName,
    Schema_name(TBL.schema_id) AS Table_SchemaName,
    TRG.name AS TriggerName,
    TRG.parent_class_desc,
    CASE WHEN TRG.is_disabled = 0 THEN 'Enabled' ELSE 'Disabled' END AS TRG_Status
FROM 
    sys.triggers TRG
INNER JOIN 
    sys.tables TBL ON TBL.OBJECT_ID = TRG.parent_id;

Explanation of the Code:

1. Lines 1-5: This section defines the columns you want to retrieve from the database using the SELECT clause.

   • TBL.name AS TableName: Selects the table name and aliases it for better readability.
   • TRG.name AS TriggerName: Selects the trigger name with an alias.
   • CASE WHEN TRG.is_disabled = 0 THEN 'Enabled' ELSE 'Disabled' END AS TRG_Status: Determines the trigger status using a CASE expression.

Running the Code:

1. Open your SQL Server Management Studio (SSMS) and connect to your desired database.
2. Copy and paste the code into a new query window.
3. Execute the query by clicking the "Run" button (or pressing F5).

• This is a visual alternative for smaller databases.
• In SSMS, navigate to your database and expand the table you're interested in.
• Look for the "Triggers" node under the table. This will list all triggers associated with that specific table.
• While not ideal for listing triggers across all tables, it can be helpful for a quick overview of a particular table's triggers.

Filtering by type in sys.objects:

• If you only need basic information about the triggers (names), you can use the sys.objects system view.
• This view includes information about all database objects, including triggers. Here's the adjusted code:

SELECT name AS TriggerName
FROM sys.objects
WHERE type = 'TR';

• This code retrieves just the name column (trigger name) and filters for objects of type TR (triggers).

Important Considerations:

• The sys.objects view doesn't provide details like table association or trigger type.
• For a more complete picture, using the sys.triggers system view with a join to sys.tables is still the recommended approach.

Additional Techniques (for Advanced Users):

• CLR Triggers (Common Language Runtime): If you need to identify CLR triggers (written in languages like C#), you might need to explore system stored procedures like sp_helpclrassembly or custom scripts to parse CLR assembly metadata.

Remember:

• Choose the method that best suits your specific needs based on the level of detail and automation required.