使用时不会复制外键约束
create table table_name ( like source_table INCLUDING ALL)'
在Postgres.如何创建包含所有外键的现有表的副本.
在CREATE TABLE … LIKE ….中没有自动创建外键的选项.
LIKE source_table [ like_option … ]
Not-null constraints are always copied to the new table. CHECK
constraints will be copied only if INCLUDING CONSTRAINTS is specified […]Indexes,PRIMARY KEY,and UNIQUE constraints on the original table
will be created on the new table only if the INCLUDING INDEXES clause
is specified.
在实践中,使用GUI工具很容易.例如,在PgAdmin III中:
>将source_table的复制声明(DDL)复制到查询工具(ctrl-e),
>编辑声明,
>执行sql.
在sql脚本中,您可以使用以下函数.重要的假设:源表外键具有正确的名称,即它们的名称包含源表名称(典型情况是什么).
create or replace function create_table_like(source_table text,new_table text) returns void language plpgsql as $$ declare rec record; begin execute format( 'create table %s (like %s including all)',new_table,source_table); for rec in select oid,conname from pg_constraint where contype = 'f' and conrelid = source_table::regclass loop execute format( 'alter table %s add constraint %s %s',replace(rec.conname,source_table,new_table),pg_get_constraintdef(rec.oid)); end loop; end $$;
使用示例:
create table base_table (base_id int primary key); create table source_table (id int primary key,base_id int references base_table); select create_table_like('source_table','new_table'); \d new_table Table "public.new_table" Column | Type | Modifiers ---------+---------+----------- id | integer | not null base_id | integer | Indexes: "new_table_pkey" PRIMARY KEY,btree (id) Foreign-key constraints: "new_table_base_id_fkey" FOREIGN KEY (base_id) REFERENCES base_table(base_id)