Postgresql 插入前的触发器按2递增序列
我正在使用PostgreSQL 9.6。我有以下顺序和表格:Postgresql 插入前的触发器按2递增序列,postgresql,Postgresql,我正在使用PostgreSQL 9.6。我有以下顺序和表格: CREATE SEQUENCE measure\u id\u seq 增量1 最小值1 最大值9223372036854775807 开始1 缓存1; 创建表度量( id integer非空默认值nextval('measure_id_seq'::regclass), 时区不为空的time_stp时间戳, val双精度不为空, 污染物字符变化(255)不为空, 桩号字符变化(255)不为空, 约束度量_pkey主键(id) ) 与(
CREATE SEQUENCE measure\u id\u seq
增量1
最小值1
最大值9223372036854775807
开始1
缓存1;
创建表度量(
id integer非空默认值nextval('measure_id_seq'::regclass),
时区不为空的time_stp时间戳,
val双精度不为空,
污染物字符变化(255)不为空,
桩号字符变化(255)不为空,
约束度量_pkey主键(id)
)
与(
OID=错误
);
“测量”表根据“污染物”和“站点”列的值划分为不同的表
为此,我有一个触发器,在将新数据插入表之前执行:
CREATE OR REPLACE FUNCTION before_insert_on_measure()
RETURNS TRIGGER LANGUAGE plpgsql as $$
DECLARE format_station TEXT := lower(replace(new.station, ' ', ''));
DECLARE format_pollutant TEXT := lower(replace(new.pollutant, ' ', ''));
BEGIN
EXECUTE format(
$f$
CREATE TABLE IF NOT EXISTS %I (
check (station = %L AND pollutant = %L)
) INHERITS (measure)
$f$,
concat('partition_measure_', format_station, '_', format_pollutant),
new.station,
new.pollutant);
EXECUTE format(
$f$
INSERT INTO %I (time_stp, val, pollutant, station)
VALUES (%L, %L, %L, %L)
$f$,
concat('partition_measure_', format_station, '_', format_pollutant),
new.time_stp,
new.val,
new.pollutant,
new.station
);
RETURN NULL;
END $$;
CREATE TRIGGER before_insert_on_measure
BEFORE INSERT ON measure
FOR EACH ROW EXECUTE PROCEDURE before_insert_on_measure();
将新数据插入表“measures”将创建正确的子表。例如,当我插入以下数据时:
INSERT INTO measure (time_stp, val, pollutant, station)
VALUES ('2015-01-01 01:00:00', 32.4, 'O3', 'Station 1');
INSERT INTO measure (time_stp, val, pollutant, station)
VALUES ('2016-01-01 01:00:00', 54, 'NO2', 'Station 2');
它创建以下表格:
- 分区测量站1
- 分区测量站2号
id time_stp val pollutant station
2 "2015-01-01 01:00:00+04" 32.4 "O3" "Station 1"
4 "2016-01-01 01:00:00+04" 54 "NO2" "Station 2"
相反,我希望:
id ...
1 ...
2 ...
似乎每个插入都会执行两次nextval(“度量值id”)
有什么建议吗
编辑:JGH提供的答案是正确的。以下是已编辑的触发器,以供参考:
CREATE OR REPLACE FUNCTION before_insert_on_measure()
RETURNS TRIGGER LANGUAGE plpgsql as $$
DECLARE format_station TEXT := lower(replace(new.station, ' ', ''));
DECLARE format_pollutant TEXT := lower(replace(new.pollutant, ' ', ''));
BEGIN
EXECUTE format(
$f$
CREATE TABLE IF NOT EXISTS %I (
check (station = %L AND pollutant = %L)
) INHERITS (measure)
$f$,
concat('partition_measure_', format_station, '_', format_pollutant),
new.station,
new.pollutant);
EXECUTE format(
$f$
INSERT INTO %I
VALUES (%L, %L, %L, %L, %L)
$f$,
concat('partition_measure_', format_station, '_', format_pollutant),
new.id,
new.time_stp,
new.val,
new.pollutant,
new.station
);
RETURN NULL;
END $$;
CREATE TRIGGER before_insert_on_measure
BEFORE INSERT ON measure
FOR EACH ROW EXECUTE PROCEDURE before_insert_on_measure();
在触发器中,对分区表执行insert语句时,必须传递new.id值。如果没有,则使用默认值,即对序列生成器的第二次调用