Given a table employee with开发者_如何转开发 columns ID(pk) and name
ID|name
--+-----
1 |John
2 |James
3 |Tom
Can I do
INSERT INTO employee (name) VALUES (Jack);
and somehow have the database auto assign the next available ID? Can a trigger do it? If so, how?
You want auto increment column. You can refer to the documentation here: http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html
You can use the AUTO INCREMENT Feature in My Sql. When you create the table, you can do something like this:
CREATE TABLE employee(
id MEDIUMINT NOT NULL AUTO_INCREMENT,
name CHAR(30) NOT NULL,
PRIMARY KEY (id)
) ENGINE=MyISAM;
Or May be use the alter table Query to modify the column ID
to have auto incremented values
Create your table with an identity autoincrement column:
CREATE TABLE table_name
(
id INTEGER AUTO_INCREMENT PRIMARY KEY,
-- other columns to follow
)
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