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postgreSQL生成建表语句

时间:2019-10-17 13:17:50      阅读:141      评论:0      收藏:0      [点我收藏+]

参考博文:https://blog.csdn.net/xiaofengtoo/article/details/84395199

修复了其函数中的bug,支持生成包含:字段(支持数组类型字段)、约束、索引(支持生成唯一索引,支持全类型索引)在内的建表语句。

生成的sql指定scheme为:【sch_租户id】,不同scheme生成规则或者不需要指定scheme直接修改下相关代码即可使用。

 

CREATE OR REPLACE FUNCTION "public"."findattname"("dbinstancename" varchar, "namespace" varchar, "tablename" varchar, "ctype" varchar)
  RETURNS "pg_catalog"."varchar" AS $BODY$
 
declare
tt oid ;
aname character varying default ‘‘;
 
begin
       tt := oid from pg_class where relname= tablename 
    and relnamespace =(select oid from pg_namespace  where nspname=namespace and nspowner=(select datdba from pg_database where datname=dbinstancename) ) ;      
       aname:=  array_to_string(
        array(
               select a.attname  from pg_attribute  a 
                where a.attrelid=tt and  a.attnum   in (        
                select unnest(conkey) from pg_constraint c where contype=ctype 
                and conrelid=tt  and array_to_string(conkey,,) is not null  
            ) 
        ),,)
    ;
    
    return aname;
end 
    
    
    $BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100

 

CREATE OR REPLACE FUNCTION "public"."showcreatetable"("dbinstancename" varchar, "namespace" varchar, "tablename" varchar, "tenantid" varchar)
  RETURNS "pg_catalog"."varchar" AS $BODY$
declare 
tableScript character varying default ‘‘;
tableNum int2 ;
 
begin
-- check db extist
tableNum:= count(*)    from pg_class  where relname=tablename and relnamespace =(
            select oid from pg_namespace where nspowner=(select datdba from pg_database where datname=dbinstancename) and nspname = namespace
            );
IF tableNum=0  then 
return ‘‘ ;
end if;
-- columns
tableScript:=tableScript ||  CREATE TABLE IF NOT EXISTS || "sch_||tenantid||".||tablename||  ( || array_to_string(
  array(
select concat( c1, c2, c3, c4, c5, c6 ) as column_line
from (
  select "||column_name||" ||   || case when data_type=ARRAY then ltrim(udt_name,_)||[] else data_type end as c1,
    case when character_maximum_length > 0 then ( || character_maximum_length || ) end as c2,
    case when numeric_precision > 0 and numeric_scale < 1 then null end as c3,
    case when numeric_precision > 0 and numeric_scale > 0 then null end as c4,
    case when is_nullable = NO then  NOT NULL end as c5,
    case when column_default is not Null then  DEFAULT end ||   || replace(column_default, ::character varying, ‘‘) as c6
  from information_schema.columns
  where table_name = tablename
    and table_catalog=dbinstancename
  and table_schema=namespace
  order by ordinal_position
) as string_columns
), , ) ||, ;
 
 
-- 约束
tableScript:= tableScript || array_to_string(
array(
    select concat( CONSTRAINT ,"||conname||" ,c ,u,p,f)   from (
        select conname,
        case when contype=c then   CHECK(|| consrc ||) end  as c  ,
        case when contype=u then   UNIQUE(|| ( select findattname(dbinstancename,namespace,tablename,u) ) ||) end as u ,
        case when contype=p then  PRIMARY KEY (|| ( select findattname(dbinstancename,namespace,tablename,p) ) ||) end  as p  ,
        case when contype=f then  FOREIGN KEY(|| ( select findattname(dbinstancename,namespace,tablename,u) ) ||) REFERENCES || 
        (select p.relname from pg_class p where p.oid=c.confrelid )  || (|| ( select findattname(dbinstancename,namespace,tablename,u) ) ||) end as  f
        from pg_constraint c
        where contype in(u,c,f,p) and conrelid=( 
            select oid  from pg_class  where relname=tablename and relnamespace =(
            select oid from pg_namespace where nspowner=(select datdba from pg_database where datname=dbinstancename) and nspname = namespace
            )
         )
    ) as t  
) ,, ) ||  ); ; 
 
-- 
/** **/
--- 获取非约束索引 column
-- CREATE UNIQUE INDEX pg_language_oid_index ON pg_language USING btree (oid); -- table pg_language
tableScript:= tableScript || array_to_string(
    array(
        select CREATE ||case when is_unique_index=true then UNIQUE INDEX else INDEX end ||" || indexrelname ||" ||  ON  || "sch_||tenantid||".||tablename||  USING ||index_type|| ( || attname || ); from (
         SELECT 
            i.relname AS indexrelname ,  x.indkey, 
            ( select array_to_string (
            array( 
                select a.attname from pg_attribute a where attrelid=c.oid and a.attnum in ( select unnest(x.indkey) )
 
                 ) 
             ,, ) )as attname, x.indisunique is_unique_index,am.amname index_type
            
           FROM pg_class c
           JOIN pg_index x ON c.oid = x.indrelid
           JOIN pg_class i ON i.oid = x.indexrelid
             join pg_am am on am.oid = i.relam
           LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
           WHERE  c.relname=tablename and i.relname not in
              ( select constraint_name from information_schema.key_column_usage  where  table_name=tablename  )
                and c.relnamespace =(
            select oid from pg_namespace where nspowner=(select datdba from pg_database where datname=dbinstancename) and nspname = namespace
            )
        )as t
) ,‘‘ );
            

 
return tableScript;
 
end
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100

 

postgreSQL生成建表语句

原文:https://www.cnblogs.com/liugh6/p/11691185.html

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