SQLite - 自动增量


SQLite AUTOINCRMENT是一个关键字,用于自动递增表中字段的值。我们可以在创建具有特定列名的表时使用AUTOINCRMENT关键字来自动递增字段值以进行自增。

关键字AUTOINCRMENT只能与 INTEGER 字段一起使用。

句法

AUTOINCRMENT关键字的基本用法如下 -

CREATE TABLE table_name(
   column1 INTEGER AUTOINCREMENT,
   column2 datatype,
   column3 datatype,
   .....
   columnN datatype,
);

例子

考虑按如下方式创建 COMPANY 表 -

sqlite> CREATE TABLE COMPANY(
   ID INTEGER PRIMARY KEY AUTOINCREMENT,
   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 ('Allen', 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 );

这将向表 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  20000.0
2           Allen       25          Texas       15000.0
3           Teddy       23          Norway      20000.0
4           Mark        25          Rich-Mond   65000.0
5           David       27          Texas       85000.0
6           Kim         22          South-Hall  45000.0
7           James       24          Houston     10000.0