【postgreSQL学习笔记】PostgreSQL分区表应用
一、环境
系统环境：Ubuntu 15.04
PostgreSQL版本：postgresql-9.4.4
二、创建主表
2.1 创建主表
test=# CREATE TABLE tbl_student( test(# id integer, test(# name varchar(20), test(# grade integer, test(# class integer, test(# age integer); CREATE TABLE test=#
2.2 创建分区表
test=# CREATE TABLE tbl_student_grade_1( test(# CHECK (grade = 1) //一年级学生 test(# ) INHERITS (tbl_student); CREATE TABLE test=# CREATE TABLE tbl_student_grade_2( CHECK (grade = 2) //二年级学生 ) INHERITS (tbl_student); CREATE TABLE test=# CREATE TABLE tbl_student_grade_3( CHECK (grade = 3) //三年级学生 ) INHERITS (tbl_student); CREATE TABLE test=# CREATE TABLE tbl_student_grade_4( CHECK (grade = 4) //四年级学生 ) INHERITS (tbl_student); CREATE TABLE test=# CREATE TABLE tbl_student_grade_5( CHECK (grade = 5) //五年级学生 ) INHERITS (tbl_student); CREATE TABLE test=# CREATE TABLE tbl_student_grade_6( CHECK (grade = 6) //六年级学生 ) INHERITS (tbl_student); CREATE TABLE test=#
2.3 分区表上建索引
test=# CREATE INDEX tbl_student_grade_1_index on tbl_student_grade_1(grade); CREATE INDEX test=# CREATE INDEX tbl_student_grade_2_index on tbl_student_grade_2(grade); CREATE INDEX test=# CREATE INDEX tbl_student_grade_3_index on tbl_student_grade_3(grade); CREATE INDEX test=# CREATE INDEX tbl_student_grade_4_index on tbl_student_grade_4(grade); CREATE INDEX test=# CREATE INDEX tbl_student_grade_5_index on tbl_student_grade_5(grade); CREATE INDEX test=# CREATE INDEX tbl_student_grade_6_index on tbl_student_grade_6(grade); CREATE INDEX test=#
对于用户来说，插入数据的时候，并不需要了解分区别的存在，也就是说表应该是一个透明的整体，用户只需要插入数据即可，不需要区分。那么我们就需要给各个分区表建立触发器来进行辅助操作。
2.4 创建触发器函数
test=# CREATE OR REPLACE FUNCTION tbl_student_insert_trigger() RETURNS TRIGGER AS $$ BEGIN IF (NEW.grade = 1) THEN INSERT INTO tbl_student_grade_1 VALUES (NEW.*); ELSEIF (NEW.grade = 2) THEN INSERT INTO tbl_student_grade_2 VALUES (NEW.*); ELSEIF (NEW.grade = 3) THEN INSERT INTO tbl_student_grade_3 VALUES (NEW.*); ELSEIF (NEW.grade = 4) THEN INSERT INTO tbl_student_grade_4 VALUES (NEW.*); ELSEIF (NEW.grade = 5) THEN INSERT INTO tbl_student_grade_5 VALUES (NEW.*); ELSEIF (NEW.grade = 6) THEN INSERT INTO tbl_student_grade_6 VALUES (NEW.*); ELSE RAISE EXCEPTION 'Date error,out of range.Fix it and try again'; END IF; RETURN NULL; END; $$ LANGUAGE plpgsql; CREATE FUNCTION test=#
2.5 创建触发器
test=# CREATE TRIGGER insert_tbl_student_trigger test-# BEFORE INSERT ON tbl_student test-# FOR EACH ROW EXECUTE PROCEDURE tbl_student_insert_trigger(); CREATE TRIGGER test=#
三、查看表
现在所有的内容准备就绪，我们来查看各个表
3.1 查看所有表
test=# \dt List of relations Schema | Name | Type | Owner --------+---------------------+-------+-------------- public | tbl_student | table | highgo-yueyf public | tbl_student_grade_1 | table | highgo-yueyf public | tbl_student_grade_2 | table | highgo-yueyf public | tbl_student_grade_3 | table | highgo-yueyf public | tbl_student_grade_4 | table | highgo-yueyf public | tbl_student_grade_5 | table | highgo-yueyf public | tbl_student_grade_6 | table | highgo-yueyf (7 rows) test=#
3.2 查看主表
test=# \d tbl_student Table "public.tbl_student" Column | Type | Modifiers --------+-----------------------+----------- id | integer | name | character varying(20) | grade | integer | class | integer | age | integer | Triggers: insert_tbl_student_trigger BEFORE INSERT ON tbl_student FOR EACH ROW EXECUTE PROCEDURE tbl_student_insert_trigger() Number of child tables: 6 (Use \d+ to list them.) test=#
3.3 查看分区表
test=# \d tbl_student_grade_1 Table "public.tbl_student_grade_1" Column | Type | Modifiers --------+-----------------------+----------- id | integer | name | character varying(20) | grade | integer | class | integer | age | integer | Indexes: "tbl_student_grade_1_index" btree (grade) Check constraints: "tbl_student_grade_1_grade_check" CHECK (grade = 1) Inherits: tbl_student test=#
四、测试
4.1 插入测试用数据
每个年级三个班，每个班有一名学生的数据，六个年级共有18名学生的数据。
test=# INSERT INTO tbl_student VALUES (1, 'David', 1, 1, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (2, 'Jim', 1, 2, 6); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (3, 'Sandy', 1, 3, 6); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (4, 'Candy', 2, 1, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (5, 'Lily', 2, 2, 8); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (6, 'Smith', 2, 3, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (7, 'Pool', 3, 1, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (8, 'Alen', 3, 2, 6); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (9, 'May', 3, 3, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (10, 'Huan', 4, 1, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (11, 'Yue', 4, 2, 8); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (12, 'Kate', 4, 3, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (13, 'Gay', 5, 1, 8); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (14, 'Jane', 5, 2, 6); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (15, 'Wolf', 5, 3, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (16, 'David', 6, 1, 6); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (17, 'David', 6, 2, 7); INSERT 0 0 test=# INSERT INTO tbl_student VALUES (18, 'David', 6, 3, 7); INSERT 0 0 test=#
4.2 再次查看主表数据
test=# SELECT * FROM tbl_student; id | name | grade | class | age ----+-------+-------+-------+----- 1 | David | 1 | 1 | 7 2 | Jim | 1 | 2 | 6 3 | Sandy | 1 | 3 | 6 4 | Candy | 2 | 1 | 7 5 | Lily | 2 | 2 | 8 6 | Smith | 2 | 3 | 7 7 | Pool | 3 | 1 | 7 8 | Alen | 3 | 2 | 6 9 | May | 3 | 3 | 7 10 | Huan | 4 | 1 | 7 11 | Yue | 4 | 2 | 8 12 | Kate | 4 | 3 | 7 13 | Gay | 5 | 1 | 8 14 | Jane | 5 | 2 | 6 15 | Wolf | 5 | 3 | 7 16 | David | 6 | 1 | 6 17 | David | 6 | 2 | 7 18 | David | 6 | 3 | 7 (18 rows) test=#
4.3 查看分区表的数据 6个年级分别查看
test=# SELECT * FROM tbl_student_grade_1; id | name | grade | class | age ----+-------+-------+-------+----- 1 | David | 1 | 1 | 7 2 | Jim | 1 | 2 | 6 3 | Sandy | 1 | 3 | 6 (3 rows) test=# SELECT * FROM tbl_student_grade_2; id | name | grade | class | age ----+-------+-------+-------+----- 4 | Candy | 2 | 1 | 7 5 | Lily | 2 | 2 | 8 6 | Smith | 2 | 3 | 7 (3 rows) test=# SELECT * FROM tbl_student_grade_3; id | name | grade | class | age ----+------+-------+-------+----- 7 | Pool | 3 | 1 | 7 8 | Alen | 3 | 2 | 6 9 | May | 3 | 3 | 7 (3 rows) test=# SELECT * FROM tbl_student_grade_4; id | name | grade | class | age ----+------+-------+-------+----- 10 | Huan | 4 | 1 | 7 11 | Yue | 4 | 2 | 8 12 | Kate | 4 | 3 | 7 (3 rows) test=# SELECT * FROM tbl_student_grade_5; id | name | grade | class | age ----+------+-------+-------+----- 13 | Gay | 5 | 1 | 8 14 | Jane | 5 | 2 | 6 15 | Wolf | 5 | 3 | 7 (3 rows) test=# SELECT * FROM tbl_student_grade_6; id | name | grade | class | age ----+-------+-------+-------+----- 16 | David | 6 | 1 | 6 17 | David | 6 | 2 | 7 18 | David | 6 | 3 | 7 (3 rows) test=#
至此，分区表建立完毕。数据自动分到了各个分区表中，方便管理。