没有任何外键约束，无法删除表中的行

Question

I am trying to delete rows from a table in SQL Server 2008 that has neither any foreign key constraints nor any triggers . When I check the message section, it is showing the rows affected but when I check the table, rows are still present. Attached is the image for reference. I am very much sure that there no constraints to this table. What could be the issue?

Answer 1

You can use sys tables to query constrints, keys, etc. Based upon these results, you can delete from your table. Please see below for a sample query which returns table constraints.

    SELECT 
    TableName = t.Name,
    ColumnName = c.Name,
    dc.type,
    dc.type_desc,
    dc.name,
    dc.definition
FROM sys.tables t
INNER JOIN sys.default_constraints dc ON t.object_id = dc.parent_object_id
INNER JOIN sys.columns c ON dc.parent_object_id = c.object_id AND c.column_id = dc.parent_column_id
where t.name = 'yourtablename'
ORDER BY t.Name

Answer 2

If there truly is no trigger on the table you're deleting from, then examine all the linked tables that have FKs to the table you're deleting from (and, in turn, all FKs to those tables). The FKs would have ON DELETE CASCADE set so that the delete actually works (instead of throwing an error), only, a trigger in any of those FK-bearing tables could be immediately re-adding the rows.

You might not necessarily see a rows affected message for all of these potential trigger operations, because triggers can set SET NOCOUNT ON before doing any DML...