Question

oracle建表id自动增长

比如我建立了user表，表里面有id、name字段。建立了student表，表里面有id、name字段，怎样实现user表里面的id自动增长。非常感谢！！！

Answer 1

SQL> CREATE SEQUENCE test_sequence2
2 increment by 1 -- 每次递增1
3 start with 1 -- 从1开始
4 nomaxvalue -- 没有最大值
5 minvalue 1 -- 最小值=1
6 NOCYCLE; -- 不循环

Sequence created.

SQL> CREATE TABLE test_create_tab2 (
2 id INT,
3 val VARCHAR(10),
4 PRIMARY KEY (id)
5 );

Table created.

SQL> CREATE OR REPLACE TRIGGER BeforeTestCreate2Insert
2 BEFORE INSERT ON test_create_tab2
3 FOR EACH ROW
4 BEGIN
5 SELECT test_sequence2.nextval INTO :new.id FROM dual;
6 END;
7 /

Trigger created.

SQL> INSERT INTO test_create_tab2(val) VALUES ('NO id');

1 row created.

SQL> INSERT INTO test_create_tab2(id, val) VALUES (1, 'id no use');

1 row created.

SQL> SELECT * FROM test_create_tab2;

ID VAL
---------- --------------------
1 NO id
2 id no use
希望能解决您的问题。

Answer 2

SQL> CREATE SEQUENCE test_sequence2
2 increment by 1 -- 每次递增1
3 start with 1 -- 从1开始
4 nomaxvalue -- 没有最大值
5 minvalue 1 -- 最小值=1
6 NOCYCLE; -- 不循环

Sequence created.

SQL> CREATE TABLE test_create_tab2 (
2 id INT,
3 val VARCHAR(10),
4 PRIMARY KEY (id)
5 );

Table created.

SQL> CREATE OR REPLACE TRIGGER BeforeTestCreate2Insert
2 BEFORE INSERT ON test_create_tab2
3 FOR EACH ROW
4 BEGIN
5 SELECT test_sequence2.nextval INTO :new.id FROM dual;
6 END;
7 /

Trigger created.

SQL> INSERT INTO test_create_tab2(val) VALUES ('NO id');

1 row created.

SQL> INSERT INTO test_create_tab2(id, val) VALUES (1, 'id no use');

1 row created.

SQL> SELECT * FROM test_create_tab2;

ID VAL
---------- --------------------
1 NO id
2 id no use
以上回答你满意么？

追问

非常感谢！！！

Answer 3

SQL> CREATE SEQUENCE test_sequence2
2 increment by 1 -- 每次递增1
3 start with 1 -- 从1开始
4 nomaxvalue -- 没有最大值
5 minvalue 1 -- 最小值=1
6 NOCYCLE; -- 不循环

Sequence created.

SQL> CREATE TABLE test_create_tab2 (
2 id INT,
3 val VARCHAR(10),
4 PRIMARY KEY (id)
5 );

Table created.

SQL> CREATE OR REPLACE TRIGGER BeforeTestCreate2Insert
2 BEFORE INSERT ON test_create_tab2
3 FOR EACH ROW
4 BEGIN
5 SELECT test_sequence2.nextval INTO :new.id FROM dual;
6 END;
7 /

Trigger created.

SQL> INSERT INTO test_create_tab2(val) VALUES ('NO id');

1 row created.

SQL> INSERT INTO test_create_tab2(id, val) VALUES (1, 'id no use');

1 row created.

SQL> SELECT * FROM test_create_tab2;

ID VAL
---------- --------------------
1 NO id
2 id no use
这样可以么？

追问

非常感谢！！！

Answer 4

可以使用Oracle的sequence实现自增长。

追问

非常感谢！！