SQL Server/T-SQL/Constraints/Default Value
Add a default value of 0 if no value specified
1> create table employee(
2> ID int,
3> name nvarchar (10),
4> salary int,
5> start_date datetime,
6> city nvarchar (10),
7> region char (1))
8> GO
1>
2> insert into employee (ID, name, salary, start_date, city, region)
3> values (1, "Jason", 40420, "02/01/94", "New York", "W")
4> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (2, "Robert",14420, "01/02/95", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (3, "Celia", 24020, "12/03/96", "Toronto", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (4, "Linda", 40620, "11/04/97", "New York", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (5, "David", 80026, "10/05/98", "Vancouver","W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (6, "James", 70060, "09/06/99", "Toronto", "N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (7, "Alison",90620, "08/07/00", "New York", "W")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (8, "Chris", 26020, "07/08/01", "Vancouver","N")
3> GO
(1 rows affected)
1> insert into employee (ID, name, salary, start_date, city, region)
2> values (9, "Mary", 60020, "06/09/02", "Toronto", "W")
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
(9 rows affected)
1>
2> -- This will add a default value of 0 if no value specified
3> ALTER TABLE Employee WITH NOCHECK
4> ADD CONSTRAINT SalaryDefaultValue DEFAULT (0) FOR Salary
5> GO
1>
2> INSERT employee (Name) VALUES ("Bedford")
3> GO
(1 rows affected)
1>
2> select * from employee
3> GO
ID name salary start_date city region
----------- ---------- ----------- ----------------------- ---------- ------
1 Jason 40420 1994-02-01 00:00:00.000 New York W
2 Robert 14420 1995-01-02 00:00:00.000 Vancouver N
3 Celia 24020 1996-12-03 00:00:00.000 Toronto W
4 Linda 40620 1997-11-04 00:00:00.000 New York N
5 David 80026 1998-10-05 00:00:00.000 Vancouver W
6 James 70060 1999-09-06 00:00:00.000 Toronto N
7 Alison 90620 2000-08-07 00:00:00.000 New York W
8 Chris 26020 2001-07-08 00:00:00.000 Vancouver N
9 Mary 60020 2002-06-09 00:00:00.000 Toronto W
NULL Bedford 0 NULL NULL NULL
(10 rows affected)
1>
2>
3> drop table employee
4> GO
1>
Add Default value constraint
7> CREATE TABLE Customers
8> (
9> CustomerNo int IDENTITY NOT NULL
10> PRIMARY KEY,
11> CustomerName varchar(30) NOT NULL,
12> Address1 varchar(30) NOT NULL,
13> Address2 varchar(30) NOT NULL,
14> City varchar(20) NOT NULL,
15> State char(2) NOT NULL,
16> Zip varchar(10) NOT NULL,
17> Contact varchar(25) NOT NULL,
18> Phone char(15) NOT NULL,
19> FedIDNo varchar(9) NOT NULL,
20> DateInSystem smalldatetime NOT NULL
21> )
22> GO
1>
2> ALTER TABLE Customers
3> ADD CONSTRAINT CN_CustomerAddress
4> DEFAULT "UNKNOWN" FOR Address1
5> GO
1>
2> drop table Customers;
3> GO
1>
2>
Set default value for column
1>
2> CREATE TABLE T (
3> int1 int,
4> bit1 bit NOT NULL DEFAULT 0,
5> rvr1 timestamp,
6> usr1 nvarchar(28) DEFAULT USER,
7> createtime datetime DEFAULT CURRENT_TIMESTAMP
8> )
9> GO
1>
2> INSERT T (int1) VALUES (1) WAITFOR DELAY "00:00:01"
3> GO
1> INSERT T (int1, bit1) VALUES (2, 0) WAITFOR DELAY "00:00:01"
2> GO
1> INSERT T (int1, bit1) VALUES (3, 1)
2> GO
(1 rows affected)
1> SELECT int1, bit1, usr1,
2> CONVERT(int, rvr1) "Timestamp as int",
3> createtime
4> FROM T
5> GO
int1 bit1 usr1 Timestamp as int createtime
----------- ---- ---------------------------- ---------------- -----------------------
1 0 dbo 5007 2006-10-14 10:53:20.827
2 0 dbo 5008 2006-10-14 10:53:21.827
3 1 dbo 5009 2006-10-14 10:53:22.827
(3 rows affected)
1>
2> UPDATE T
3> set bit1 = 1
4> WHERE int1 = 2
5> GO
(1 rows affected)
1>
2> SELECT int1, bit1, usr1,
3> CONVERT(int, rvr1) "Timestamp as int",
4> createtime
5> FROM T
6> GO
int1 bit1 usr1 Timestamp as int createtime
----------- ---- ---------------------------- ---------------- -----------------------
1 0 dbo 5007 2006-10-14 10:53:20.827
2 1 dbo 5010 2006-10-14 10:53:21.827
3 1 dbo 5009 2006-10-14 10:53:22.827
(3 rows affected)
1>
2> drop table t
3> GO
1>