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

I agree we should reject CREATE TABLE t (a INT PRIMARY KEY); ALTER TABLE t ADD COLUMN b INT PRIMARY KEY;, but what to do in the case that the primary key is the implicit rowid primary key is less ...

This commit extends cockroachdb#86071 to support `ALTER TABLE ... ADD PRIMARY KEY` in implicit transactions in the case that the existing primary key uses the default `rowid` primary key. It adopts ...

Adding a primary key using alter command:alter command is generally used to modify table . it can be used to add columns or to remove columns. using alter command we can also add or remove a key from ...

If you work with relational databases, you probably know that each table needs a primary key. But what is the purpose of a primary key and how does it help you manage your data?