Learn how to use CREATE TABLE, ALTER TABLE, and CONSTRAINT to create, modify, and view primary and foreign keys in SQL DB2 tables.

ADD foreign key (PersonID) references Persons (ID); -- you can't drop this constraint because it is not have constraint_name Drop constraint FirstName; -- you can't use name column to drop constraint, ...

Learn how to create, test, validate, and optimize foreign keys in SQL Server using queries and tools. Improve your data quality and integrity with foreign keys.

Question, if I'm truncating tables I need to take care of any foreign key constraints before doing so. Is it better to Drop, Truncate and Add back the Foreign Key or Disable it through some ...

-- The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. -- A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in ...

By using cascading referential integrity constraints, you can define the actions that SQL Server 2005 takes when a user tries to delete or update a key to which existing foreign keys point.

I am trying to create to 2 tables and inserting data into them but I am getting this error Creating Athlete the table failed SQLSTATE [23000]: Integrity constraint violation: 1217 Cannot delete or ...

Foreign key 'geneassay_fk' references invalid column 'geneassay' in referencing table 'b_SequencingData_seq'. Msg 1750, Level 16, State 0, Line 43 Could not create constraint.