我有一个表输入和一个派生表参数
CREATE TABLE Configurables
(
id SERIAL PRIMARY KEY
);
CREATE TABLE Inputs
(
configurable integer REFERENCES Configurables( id ),
name text,
time timestamp,
PRIMARY KEY( configurable, name, time )
);
CREATE TABLE Parameters
(
configurable integer,
name text,
time timestamp,
value text,
FOREIGN KEY( configurable, name, time ) REFERENCES Inputs( configurable, name, time )
);
以下查询检查参数是否已更改或尚不存在,并插入具有新值的参数。
QString PostgreSQLQueryEngine::saveParameter( int configurable, const QString& name, const QString& value )
{
return QString( "\
INSERT INTO Inputs( configurable, name, time ) \
WITH MyParameter AS \
( \
SELECT configurable, name, time, value \
FROM \
( \
SELECT configurable, name, time, value \
FROM Parameters \
WHERE (configurable = %1) AND (name = '%2') AND time = \
( \
SELECT max( time ) \
FROM Parameters \
WHERE (configurable = %1) AND (name = '%2') \
) \
UNION \
SELECT %1 AS configurable, '%2' AS name, '-infinity' AS time, NULL AS value \
)AS foo \
) \
SELECT %1 AS configurable, '%2' AS name, 'now' AS time FROM MyParameter \
WHERE time = (SELECT max(time) FROM MyParameter) AND (value <> '%3' OR value IS NULL); \
\
INSERT INTO Parameters( configurable, name, time, value ) \
WITH MyParameter AS \
( \
SELECT configurable, name, time, value \
FROM \
( \
SELECT configurable, name, time, value \
FROM Parameters \
WHERE (configurable = %1) AND (name = '%2') AND time = \
( \
SELECT max( time ) \
FROM Parameters \
WHERE (configurable = %1) AND (name = '%2') \
) \
UNION \
SELECT %1 AS configurable, '%2' AS name, '-infinity' AS time, NULL AS value \
)AS foo \
) \
SELECT %1 AS configurable, '%2' AS name, 'now' AS time, '%3' AS value FROM MyParameter \
WHERE time = (SELECT max(time) FROM MyParameter) AND (value <> '%3' OR value IS NULL); \
" ).arg( configurable ).arg( name ).arg( value );
}
我应该如何最好地解决 2 MyParameter 子查询的重复?
有关清理此类查询的任何其他提示