DEFAULT

SQL DEFAULT constraints in CREATE TABLE

The following SQL creates DEFAULT in the column "City, when creating a table" Persons ":

My SQL / SQL Server / Oracle / MS Access:

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CREATE TABLE Persons (
P_Id int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255) DEFAULT 'Sandnes'
)

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CREATE TABLE Orders (
O_Id int NOT NULL,
OrderNo int NOT NULL,
P_Id int,
OrderDate date DEFAULT GETDATE()
)

SQL DEFAULT Restrictions on ALTER TABLE

The following SQL creates DEFAULT in the column "City, when the table" Persons "has already been established:

MySQL:

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ALTER TABLE Persons
ALTER City SET DEFAULT 'SANDNES'

SQL Server / Oracle / MS Access:

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ALTER TABLE Persons
ALTER COLUMN City SET DEFAULT 'SANDNES'

Removing DEFAULT

To remove a constraint DEFAULT, use the following SQL:

MySQL:

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ALTER TABLE Persons
ALTER City DROP DEFAULT

SQL Server / Oracle / MS Access:

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ALTER TABLE Persons
ALTER COLUMN City DROP DEFAULT