转一个有意思的利用存储过程备份恢复PostgreSQL

【转自 housonglin1213 的博客】http://blog.csdn.net/housonglin1213/article/details/51005540

1、自定义函数脚本备份

CREATE OR REPLACE FUNCTION function_sql_dump()
  RETURNS void AS
$BODY$
DECLARE
    my_cur refcursor;
    isexisted integer:=0;
    oid_var oid;
    role_oid oid;
BEGIN
    --判断临时表是否已经存在
    select count(*) into isexisted from pg_class where relname = 'function_sql_table';
    --如果已经存在则删除
    IF(isexisted !=0)THEN
    DROP TABLE function_sql_table;
    END IF;
    --创建临时表-用于存储函数sql语句
    CREATE TABLE function_sql_table(t TEXT);
    select oid into role_oid from pg_roles where rolname='smartsys';
    IF role_oid is null THEN
        return;
    END IF;
    OPEN my_cur FOR select oid from pg_proc where proowner=role_oid order by oid;
    LOOP
    FETCH my_cur INTO oid_var;
        IF NOT FOUND THEN EXIT; END IF;
        INSERT INTO function_sql_table(t) VALUES (pg_get_functiondef(oid_var));
    END LOOP;
    CLOSE my_cur;
    COPY function_sql_table TO 'D:/PostgreSQL/9.5/function_sql_bak.sql';
end
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION function_sql_dump()
  OWNER TO smartsys;

补充说明：备份出的sql文件是存储于postgresql数据库服务所在服务器的目录中的。smartsys为数据库用户名。 
注：pg_get_functiondef(oid_var)方法返回text类型自带换行（效果如下图，需要纵向拉伸才能看到全部信息）

2、已备份自定义函数脚本的恢复

CREATE OR REPLACE FUNCTION function_sql_restore(func_name character varying)
  RETURNS void AS
$BODY$
DECLARE
    my_cur refcursor;
    isexisted integer:=0;
    oid_var oid;
    sql_str text;
    sql_var varchar(1024);
BEGIN
    --判断临时表是否已经存在
    select count(*) into isexisted from pg_class where relname = 'function_sql_table';
    --如果已经存在则删除
    IF(isexisted !=0)THEN
    DROP TABLE function_sql_table;
    END IF;
    --创建临时表-用于存储函数sql语句
    CREATE TABLE function_sql_table(t TEXT);   

    COPY function_sql_table from 'D:/PostgreSQL/9.5/function_sql_bak.sql';  

    IF(func_name is not null)THEN
        OPEN my_cur FOR select t from function_sql_table where t like '%'||func_name||'%';
    ELSE
        OPEN my_cur FOR select t from function_sql_table;
    END IF;
    LOOP
        FETCH my_cur INTO sql_str;
        IF NOT FOUND THEN EXIT; END IF;
        execute sql_str;
    END LOOP;
    CLOSE my_cur;
end
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

其中该方法中的参数：func_name为函数名称，即：指定要恢复的函数。