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Mysql 分區介紹(二) —— RANGE分區

mysql分區 mysql rank分區 數據庫分區

通過範圍的方式進行分區, 為每個分區給出一定的範圍, 範圍必須是連續的並且不能重復, 使用VALUES LESS THAN操作符<br />

讓我們先來創建一個range分區的表

CREATE TABLE employees (
    id INT NOT NULL,
    fname VARCHAR(30),
    lname VARCHAR(30),
    hired DATE NOT NULL DEFAULT ‘1970-01-01‘,
    separated DATE NOT NULL DEFAULT ‘9999-12-31‘,
    job_code INT NOT NULL,
    store_id INT NOT NULL
)
PARTITION BY RANGE (store_id) (
    PARTITION p0 VALUES LESS THAN (6),
    PARTITION p1 VALUES LESS THAN (11),
    PARTITION p2 VALUES LESS THAN (16),
    PARTITION p3 VALUES LESS THAN (21)
);

store_id 小於6的, 會被放入第一個分區, 小於11的會放入第二個分區。<br>
如果我的store_id大於21怎麽辦呢?, 所以我們得修改一下這個創建分區的方式。

CREATE TABLE employees (
    id INT NOT NULL,
    fname VARCHAR(30),
    lname VARCHAR(30),
    hired DATE NOT NULL DEFAULT ‘1970-01-01‘,
    separated DATE NOT NULL DEFAULT ‘9999-12-31‘,
    job_code INT NOT NULL,
    store_id INT NOT NULL
)
PARTITION BY RANGE (store_id) (
    PARTITION p0 VALUES LESS THAN (6),
    PARTITION p1 VALUES LESS THAN (11),
    PARTITION p2 VALUES LESS THAN (16),
    PARTITION p3 VALUES LESS THAN (21),
    PARTITION p4 VALUES LESS THAN (MAXVALUE)
);

增加了一個MAXVALUE, MAXVALUE的意思是, 大於21的數據都會放入這個分區, 當然, 還有另外一種方式去避免這個問題, 就是在INSERT的時候增加IGNORE關鍵字。<br />

分區鍵類型為時間轉時間戳 <br />
可以使用UNIX-TIMESTAMP()

CREATE TABLE quarterly_report_status (
    report_id INT NOT NULL,
    report_status VARCHAR(20) NOT NULL,
    report_updated TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
)
PARTITION BY RANGE ( UNIX_TIMESTAMP(report_updated) ) (
    PARTITION p0 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2008-01-01 00:00:00‘) ),
    PARTITION p1 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2008-04-01 00:00:00‘) ),
    PARTITION p2 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2008-07-01 00:00:00‘) ),
    PARTITION p3 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2008-10-01 00:00:00‘) ),
    PARTITION p4 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2009-01-01 00:00:00‘) ),
    PARTITION p5 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2009-04-01 00:00:00‘) ),
    PARTITION p6 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2009-07-01 00:00:00‘) ),
    PARTITION p7 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2009-10-01 00:00:00‘) ),
    PARTITION p8 VALUES LESS THAN ( UNIX_TIMESTAMP(‘2010-01-01 00:00:00‘) ),
    PARTITION p9 VALUES LESS THAN (MAXVALUE)
);

除了UNIX_TIMESTAMP外,其他涉及到時間戳的表達式都是不被允許的

基於時間數字的分區 <br />

CREATE TABLE members (
    firstname VARCHAR(25) NOT NULL,
    lastname VARCHAR(25) NOT NULL,
    username VARCHAR(16) NOT NULL,
    email VARCHAR(35),
    joined DATE NOT NULL
)
PARTITION BY RANGE(YEAR(joined) ) (
    PARTITION p0 VALUES LESS THAN (1960),
    PARTITION p1 VALUES LESS THAN (1970),
    PARTITION p2 VALUES LESS THAN (1980),
    PARTITION p3 VALUES LESS THAN (1990),
    PARTITION p4 VALUES LESS THAN MAXVALUE
);

Mysql 分區介紹(二) —— RANGE分區