Как добавить ограничения по умолчанию в MySQL
ALTER TABLE "name_table" ALTER "name_column"
SET DEFAULT value_default;
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ALTER TABLE "name_table" ALTER "name_column"
SET DEFAULT value_default;
//Sql Server
//Add a table
ALTER TABLE clients ADD Points INT DEFAULT 0
//Edit an existing table
ALTER TABLE clients ADD CONSTRAINT points DEFAULT 0 FOR Points
ALTER TABLE PERSON
ADD IS_ACTIVE VARCHAR2(1) DEFAULT 'N' NOT NULL
CREATE TABLE Persons (
ID int NOT NULL,
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Age int,
City varchar(255) DEFAULT 'Sandnes'
);
Sets a default value for a column;
Example 1 (MySQL): Creates a new table called Products which has a
name column with a default value of ‘Placeholder Name’ and an available_
from column with a default value of today’s date.
CREATE TABLE products (
id int,
name varchar(255) DEFAULT 'Placeholder Name',
available_from date DEFAULT GETDATE()
);
Example 2 (MySQL): The same as above, but editing an existing table.
ALTER TABLE products
ALTER name SET DEFAULT 'Placeholder Name',
ALTER available_from SET DEFAULT GETDATE();
CREATE TABLE College (
college_id INT PRIMARY KEY,
college_code VARCHAR(20),
college_country VARCHAR(20) DEFAULT 'US'
);