将序列链接到hsqldb中的标识 [英] Link a sequence with to an identity in hsqldb

问题描述

在PostgreSql中，可以定义一个序列并将其用作表的主键.在HsqlDB中，仍然可以完成创建一个自动递增的标识列，该列不链接到任何用户定义的序列.是否可以使用用户定义的序列作为HsqlDB中自动增量标识列的生成器?

In PostgreSql, one can define a sequence and use it as the primary key of a table. In HsqlDB, one can still accomplish creating an auto-increment identity column which doesn't link to any user defined sequence. Is it possible to use a user defined sequence as the generator of an auto-increment identity column in HsqlDB?

PostgreSql中的示例SQL:

Sample sql in PostgreSql:

CREATE SEQUENCE seq_company_id START WITH 1;

CREATE TABLE company (
  id bigint PRIMARY KEY DEFAULT nextval('seq_company_id'),
  name varchar(128) NOT NULL CHECK (name <> '')
);

HsqlDB中的等效项是什么?

What's the equivalent in HsqlDB?

谢谢.

推荐答案

在2.0版中，没有直接的功能.您可以在表上定义一个BEFORE INSERT触发器来执行此操作:

In version 2.0, there is no direct feature for this. You can define a BEFORE INSERT trigger on the table to do this:

CREATE TABLE company ( id bigint PRIMARY KEY, name varchar(128) NOT NULL CHECK (name <> '') );

CREATE TRIGGER trigg BEFORE INSERT
ON company REFERENCING NEW ROW AS newrow 
FOR EACH ROW
SET newrow.id = NEXT VALUE FOR seq_company_id;

并插入而不使用任何vlue作为ID

and insert without using any vlue for id

插入公司VALUES空值，测试"

INSERT INTO company VALUES null, 'test'

HSQLDB 2.1和更高版本的更新:已添加了一项功能来支持此功能.

Update for HSQLDB 2.1 and later: A feature has been added to support this.

CREATE SEQUENCE SEQU
CREATE TABLE company ( id bigint GENERATED BY DEFAULT AS SEQUENCE SEQU PRIMARY KEY, name varchar(128) NOT NULL CHECK (name <> '') );

请参见创建表"下的指南" http://hsqldb.org/doc/2.0/guide/databaseobjects-chapt.html#dbc_table_creation

See the Guide under CREATE TABLE http://hsqldb.org/doc/2.0/guide/databaseobjects-chapt.html#dbc_table_creation

此外，2.1和更高版本具有PostgreSQL兼容模式，在该模式下，它接受PostgreSQL CREATE TABLE语句，该语句引用DEFAULT子句中的序列并将其转换为HSQLDB语法.

In addition, 2.1 and later has a PostgreSQL compatibility mode in which it accepts the PostgreSQL CREATE TABLE statement that references the sequence in the DEFAULT clause and translates it to HSQLDB syntax.

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