On Transact SQL language the Msg 3726 Level 16 - Could not drop object because it is referenced by a FOREIGN KEY constraint.

Msg 3726 Level 16 Example:

Create tables

USE model;
GO
create table Test_1
(id int not null primary key,
name varchar(500) not null);
GO
create table Test_2
(id int not null primary key,
name varchar(500) not null,
constraint FK_TestID
foreign key (id) references Test_1(id));
GO

Invalid statement:

USE model;
GO
DROP TABLE Test_1;
GO

Correct statement:

USE model;
GO
DROP TABLE Test_2;
GO
DROP TABLE Test_1;
GO

Other error messages:

• Is not a constraint
• Create View or Function failed because no column name was specified
• Cannot define PRIMARY KEY constraint on nullable column in table
• Column is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause
• String or binary data would be truncated
• The database name component of the object qualifier must be the name of the current database
• No item by the name of '%' could be found in the current database.