AUTO INCREMENT(自动增长) 会在新记录插入表中时生成一个唯一的数字,PostgreSQL 使用序列来标识字段的自增长,数据类型有 smallserial、serial 和 bigserial 。
SERIAL 数据类型的基本用法如下-
CREATE TABLE tablename ( colname SERIAL );
考虑如下创建的COMPANY表-
链接:https://www.learnfk.comhttps://www.learnfk.com/postgresql/postgresql-using-autoincrement.html
来源:LearnFk无涯教程网
testdb=# CREATE TABLE COMPANY( ID SERIAL PRIMARY KEY, NAME TEXT NOT NULL, AGE INT NOT NULL, ADDRESS CHAR(50), SALARY REAL );
现在,将以下记录插入表COMPANY-
INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( 'Paul', 32, 'California', 20000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ('Learnfk', 25, 'Texas', 15000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ('Teddy', 23, 'Norway', 20000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( 'Mark', 25, 'Rich-Mond ', 65000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( 'David', 27, 'Texas', 85000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( 'Kim', 22, 'South-Hall', 45000.00 ); INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( 'James', 24, 'Houston', 10000.00 );
这将在表COMPANY中插入7个元组,并且COMPANY将具有以下记录-
id | name | age | address | salary ----+-------+-----+------------+-------- 1 | Paul | 32 | California | 20000 2 | Learnfk | 25 | Texas | 15000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000
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