SQLite Autoincrement（自动递增）

SQLite 的 AUTOINCREMENT 是一个关键字，用于表中的字段值自动递增。我们可以在创建表时在特定的列名称上使用 AUTOINCREMENT 关键字实现该字段值的自动增加。

语法

AUTOINCREMENT 关键字的基本用法如下：

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

实例

假设要创建的 COMPANY 表如下所示：

sqlite> CREATE TABLE COMPANY(
   ID INTEGER PRIMARY KEY   AUTOINCREMENT,
   NAME           TEXT      NOT NULL,
   AGE            INT       NOT NULL,
   ADDRESS        CHAR(50),
   SALARY         REAL
);

现在，向 COMPANY 表插入以下记录：

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 COMPANY 表插入 7 个元组，此时 COMPANY 表的记录如下：

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