設置分片規則
各種表類型的分片規則DDL語法，如下表所示：
| 表類型 | 語法 | 示例 |
|---|---|---|
| 分片表 | sharding @@table name='' set type='sharding' and sharding_algo='' and sharding_id='' [ and algo_parameter='algo_value']… [and dn='']; | sharding @@table name='employee' set type='sharding' and sharding_algo='PartitionByEnumAndStringMod' and map_file='{"BJ":"0","SH":"1"}' and default_node='2' and sharding_id='employee_id' and sharding_area='area_id' and dn='drdstest_1,drdstest_2,drdstest_3'; |
| 分片表+庫內分表 | sharding @@table name='' set type='inner' and sharding_algo='' and sharding_id='' [ and algo_parameter='algo_value']… and inner_sharding_algo='' and inner_sharding_id='' [ and inner_algo_parameter='algo_value']… and inner_total='' [and dn='']; | sharding @@table name=’employee’ set type='inner' and sharding_algo='PartitionByFileMap' and map_file='{"1":"0","2":"1"}' and default_node='0' and sharding_id='employee_id' and inner_sharding_algo='PartitionByDateRange' and inner_sharding_id='area_id' and inner_start_date='2018-07-10' and inner_time_unit_len='1' and inner_time_unit_type='year' and inner_total='2' and dn='drdstest_1,drdstest_2'; |
| 分桶表 | sharding @@table name='' set type='sharding' and sharding_algo='' and sharding_id='' [ and algo_parameter='algo_value']… and buckets=’’ [and dn='']; | sharding @@table name='bucket' set type='sharding' and sharding_algo='PartitionByFileMap' and map_file='{"1":"0","2":"1","3":"2"}' and default_node='0' and sharding_id='employee_id' and buckets='2'; |
| 單片表+庫內分表 | sharding @@table name='' set type=' inner ' and inner_sharding_algo='' and sharding_id='' [ and inner_algo_parameter='algo_value']… and inner_total='' and dn=''; | sharding @@table name='single_inner' set type='inner' and inner_sharding_algo='PartitionByMod' and inner_sharding_id='employee_id' and inner_total='2' and dn='drdstest_1'; |
| 單片表 | sharding @@table name='' set type=' single ' and dn=''; | sharding @@table name='single' set type='single' and dn='drdstest_1'; |
| 全局表 | sharding @@table name='' set type='global' [and dn='']; | sharding @@table name='global' set type='global'; |
分片算法
設置分片規則時需要使用到分片算法，總共有7種分片算法，如下表所示：
| 分片算法名稱 | 分片算法ID | 算法參數及示例 | 是否可用于庫內分表 |
|---|---|---|---|
| 取模分片 | PartitionByMod | 是 | |
| 字符串hashCode取模分片 | PartitionByStringMod | 是 | |
| 枚舉分片 | PartitionByFileMap |
| 否 |
| 時間范圍分片 | PartitionByDateRange |
| 是 |
| 枚舉分組取模分片 | PartitionByEnumAndMod |
| 否 |
| 枚舉分組字符串hashCode取模分片 | PartitionByEnumAndStringMod |
| 否 |
數值類型Range分片 | PartitionByIntRange |
注意
|
