在Java应用程序中生成12位唯一编号

Question

I've to store user profiles in LDAP with 12 digits unique ID, so thought of using database by creating a sequence and accessing it in Java code(seq.nextVal()). But our company only supports mysql, but mysql don't support sequence.

Is there a work around to achieve this using mysql.

Answer 1

MySQL supports auto increment on INTEGER data type. Refer to

http://dev.mysql.com/doc/refman/5.0/en/example-auto-increment.html

If you want to make the field UNIQUE , then you can set it as PRIMARY KEY .

As an example, you can use ID BIGINT PRIMARY KEY AUTO INCREMENT as your field.

---

If you need this value in your Java application, you can:

• Generate the id in your MySQL database

• Get the value in your Java application

• Use the value to save it in your LDAP

As a test, this will assure that all your elements have 12 digits (based in your last comment):

CREATE TABLE uniqueids(id BIGINT PRIMARY KEY AUTO_INCREMENT);

INSERT INTO uniqueids VALUES(100000000000);

INSERT INTO uniqueids VALUES(null);

SELECT *
FROM uniqueids

Tested on MySQL 5.0

SQL Fiddle: http://www.sqlfiddle.com/#!2/8c508f/1