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Managing Sharded Table

Last updated: 2024-01-06 17:33:30
    This document describes how to perform simple database operations on a sharded table.

    Creating a table

    For the specific differences among sharded, non-sharded, and broadcast tables, see Overview.
    For the restrictions on selecting the shardkey, see Creating Tables.
    You need the specify the shardkey when creating a sharded table. Below is the sample code:
    mysql> create table test1(id int primary key,name varchar(20),addr varchar(20))shardkey=id;
    Query OK,0 rows affected(0.15 sec)

    Inserting data

    The insert field must contain a shardkey; otherwise, the statement will be rejected.
    Insert data to the newly created table. Below is the sample code:
    mysql> insert into test1(id,name) VALUES(1,'test');
    Query OK,1 rows affected(0.08 sec)
    mysql> insert into test3(name,addr) values('example','shenzhen');
    ERROR 7013 (HY000): Proxy ERROR:get_shardkeys return error

    Querying data

    We recommend that you carry a shardkey when querying data, so that the corresponding shard will be automatically redirected to through distributed routing, delivering the highest efficiency; otherwise, the distributed system will automatically perform a full-table scan and aggregate the results on the gateway, which is less efficient.
    Below is the sample code for data query:
    mysql> select id from test1 where id=1;

    Deleting data

    The delete field must contain a WHERE condition. We recommend that you include the shardkey in the WHERE condition.
    Below is the sample code for data deletion:
    mysql> delete from test1 where id=1;
    Query OK, 1 row affected (0.02 sec)
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