在PostgreSQL中设置变量函数/触发器

Question

我试图在时间方面在PostgreSQL数据库中创建分区。虽然下面的函数/触发器是我在大多数情况下遇到的服务器，但我仍然需要找出将表名和模式名称设置为参数的方法。正如我们计划通过更改参数值来为不同的表和模式运行相同的触发器。任何帮助都非常感谢，因为我几乎没有任何使用函数/触发器的经验。

CREATE OR REPLACE FUNCTION 
myschema.server_partition_function() 
RETURNS TRIGGER AS 
$BODY$ 
DECLARE 
_new_time int; 
_tablename text; 
_startdate text; 
_enddate text; 
_result record; 
BEGIN 
--Takes the current inbound "time" value and determines when midnight is for the given date 
_new_time := ((NEW."time"/86400)::int)*86400; 
_startdate := to_char(to_timestamp(_new_time), 'YYYY-MM-DD'); 
_tablename := 'server_'||_startdate; 

-- Check if the partition needed for the current record exists 
PERFORM 1 
FROM pg_catalog.pg_class c 
JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace 
WHERE c.relkind = 'r' 
AND c.relname = _tablename 
AND n.nspname = 'myschema'; 

-- If the partition needed does not yet exist, then we create it: 
-- Note that || is string concatenation (joining two strings to make one) 
IF NOT FOUND THEN 
_enddate:=_startdate::timestamp + INTERVAL '1 day'; 
EXECUTE 'CREATE TABLE myschema.' || quote_ident(_tablename) || ' (
CHECK ("time" >= EXTRACT(EPOCH FROM DATE ' || quote_literal(_startdate) || ') 
AND "time" < EXTRACT(EPOCH FROM DATE ' || quote_literal(_enddate) || ') 
) 
) INHERITS (myschema.server_master)'; 

-- Table permissions are not inherited from the parent. 
-- If permissions change on the master be sure to change them on the child also. 
EXECUTE 'ALTER TABLE myschema.' || quote_ident(_tablename) || ' OWNER TO postgres'; 
EXECUTE 'GRANT ALL ON TABLE myschema.' || quote_ident(_tablename) || ' TO my_role'; 

-- Indexes are defined per child, so we assign a default index that uses the partition columns 
EXECUTE 'CREATE INDEX ' || quote_ident(_tablename||'_indx1') || ' ON myschema.' || quote_ident(_tablename) || ' (time, id)'; 
END IF; 

-- Insert the current record into the correct partition, which we are sure will now exist. 
EXECUTE 'INSERT INTO myschema.' || quote_ident(_tablename) || ' VALUES ($1.*)' USING NEW; 
RETURN NULL; 
END; 
$BODY$ 
LANGUAGE plpgsql; 

Answer 1

您可能需要使用一些动态触发特殊变量。当触发被调用时，PostgreSQL自动使用特殊的变量提供一些值：http://www.postgresql.org/docs/current/static/plpgsql-trigger.html

_tablename := TG_TABLE_NAME || '_' || _startdate; 
_schemaname := TG_TABLE_SCHEMA || '_partitions';