alter-table Archives

MySQL, Programming

IT Nursery

How to add not null constraint to existing column in MySQL

I have table name called “Person” with following column names P_Id(int), LastName(varchar), FirstName (varchar). I forgot to give NOT NULL Constraint to P_Id. ...

June 2, 2022
0 Comments

Programming, sql

IT Nursery

How to alter a column’s data type in a PostgreSQL table?

Entering the following command into a PostgreSQL interactive terminal results in an error: ALTER TABLE tbl_name ALTER COLUMN col_name varchar (11); What is ...

June 2, 2022
0 Comments

Programming, sql-server

IT Nursery

Can I create a named default constraint in an add column statement in SQL Server?

In SQL Server, I have a new column on a table: ALTER TABLE t_tableName ADD newColumn NOT NULL This fails because I specify ...

June 2, 2022
0 Comments

Programming, sql

IT Nursery

Postgresql – change the size of a varchar column to lower length

I have a question about the ALTER TABLE command on a really large table (almost 30 millions rows). One of its columns is ...

June 1, 2022
0 Comments

Programming, sql-server

IT Nursery

Alter column, add default constraint

I have a table and one of the columns is “Date” of type datetime. We decided to add a default constraint to that ...

May 31, 2022
0 Comments

MySQL, Programming

IT Nursery

How do I add more members to my ENUM-type column in MySQL?

The MySQL reference manual does not provide a clearcut example on how to do this. I have an ENUM-type column of country names ...

May 30, 2022
0 Comments

MySQL, Programming

IT Nursery

ALTER TABLE to add a composite primary key

I have a table called provider. I have three columns called person, place, thing. There can be duplicate persons, duplicate places, and duplicate ...

May 28, 2022
0 Comments

Programming, sql

IT Nursery

Alter a MySQL column to be AUTO_INCREMENT

I’m trying to modify a table to make its primary key column AUTO_INCREMENT after the fact. I have tried the following SQL, but ...

May 27, 2022
0 Comments

SQL Server add auto increment primary key to existing table

As the title, I have an existing table which is already populated with 150000 records. I have added an Id column (which is ...

May 17, 2022
0 Comments

How can I add a column that doesn’t allow nulls in a Postgresql database?

I’m adding a new, “NOT NULL” column to my Postgresql database using the following query (sanitized for the Internet): ALTER TABLE mytable ADD ...

May 17, 2022
0 Comments