COALESCE

PostgreSQL

コウアレス (if objects or ideas coalesce, they combine to form one single group ( quoted from longman )) 引数を走査していき、NULL ではない初めの値を返す引数が全て NULL の場合は NULL を返す CREATE TABLE staffs( id INTEGER NOT NULL, name CH…

2015-10-20

SQL ALL

PostgreSQL

CREATE TABLE cardpoints ( id INTEGER NOT NULL, pointedlocation CHAR(32) NOT NULL, point INTEGER NOT NULL CONSTRAINT points_point_range CHECK(point BETWEEN 0 AND 15000), PRIMARY KEY(id, pointedlocation) ); INSERT INTO cardpoints (id, pointe…

2015-10-18

Read View 作成

PostgreSQL

CREATE TABLE trial_table ( trial_id INTEGER NOT NULL, name CHAR(20) NOT NULL, age INTEGER NOT NULL CONSTRAINT trial_age_range CHECK(age BETWEEN 0 AND 200), PRIMARY KEY(trial_id) ); INSERT INTO trial_table ( trial_id, name, age ) VALUES ( 1…

2015-10-17

interval, timestamp, date, time の違い

PostgreSQL

interval timestamp, date, time の時間を変動させる時に利用する関数以下の sql と結果を参照 (RDBMS ごとに文法が違うので注意) timestamp 日付と時刻 SELECT (timestamp'2014-10-17 22:00:00') AS timestamp_col; timestamp_col --------------------- 2…

2015-10-17

static field initiate optimize

Java

src | + -- jp.ymatsukawa | + -- constructor | | | + -- InstanceAble.java + -- Main.java jp.ymatsukawa/Main.java package jp.ymatsukawa; import jp.ymatsukawa.constructor.InstantiateAble; import java.util.Calendar; public class Main { public …

2015-10-17

Java constructor

Java

2015-10-16

update or delete on table "foreigns" violates foreign key constraint "to_foreigns_to_foreigns_id_fkey" on table "to_foreigns"

PostgreSQL

CREATE TABLE foreigns ( foreigns_id INTEGER NOT NULL, PRIMARY KEY(foreigns_id) ); CREATE TABLE to_foreigns ( to_foreigns_id INTEGER NOT NULL REFERENCES foreigns(foreigns_id), PRIMARY KEY(to_foreigns_id) ); INSERT INTO foreigns (foreigns_id…

2015-10-16

INTERVAL 型

PostgreSQL

型の一種(査読中) PostgreSQL で以下の動作確認 SELECT current_date; date ------------ 2015-10-15 (1 row) CREATE TABLE times ( test_date DATE NOT NULL ); INSERT INTO times VALUES ('2015-10-15'); INSERT INTO times VALUES ('2015-10-16'); INSERT…