T-SQL CREATE TABLE Examples
Here are various code examples for creating a table with Transact-SQL (T-SQL).
The following code creates a table called Artists
in the Music
database. The table has 3 columns called ArtistId
, ArtistName
, and ActiveFrom
, each with a different data type.
In most cases, you'll probably want to add a primary key and perhaps some other constraints. See below for examples.
Add an Identity Column
This example sets the ArtistId
as an identity column. This means that the value for that column will be automatically populated as an incrementing value (each row's value is incremented from the previous row). The 1,1
specifies that the value will start at 1
and it will increment by 1
each time (i.e. 1, 2, 3,... etc).
Add a NOT NULL
Constraint
A NOT NULL
constraint ensures that there are no null values in the column. Here we add a NOT NULL
constraint to the first two columns.
Add a Primary Key Constraint
A primary key constraint sets that column the primary key for the table.
Create a Foreign Key
This example creates an Artists
table and an Albums
table, then creates a relationship between them. We do this by creating a foreign key constraint on the Albums
table. We specify that the Albums.ArtistId
column is a foreign key to the Artists.ArtistId
column.
Create a DEFAULT
Definition
A DEFAULT
definition is used to provide a default value for a column. The default value is used when no value has been supplied during an INSERT
or UPDATE
operation.
Here's what that might look like within a CREATE TABLE
statement:
Create a UNIQUE
Constraint
A UNIQUE
constraint is used to enforce uniqueness on nonprimary key columns.
Now, if someone tries to insert a duplicate value into the Genre
column, an error will occur.
Create a CHECK
Constraint
A CHECK
constraint is used to limit the values that are accepted by one or more columns.
Here's what that might look like within a CREATE TABLE
statement: