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Sharding

Background

The Java API rule configuration for data sharding, which allows users to create ShardingSphereDataSource objects directly by writing Java code, is flexible enough to integrate various types of business systems without relying on additional jar packages.

Parameters

Root Configuration

Class name: org.apache.shardingsphere.sharding.api.config.ShardingRuleConfiguration

Attributes:

Name DataType Description Default Value
tables (+) Collection<ShardingTableRuleConfiguration> Sharding table rules -
autoTables (+) Collection<ShardingAutoTableRuleConfiguration> Sharding auto table rules -
bindingTableGroups (*) Collection<String> Binding table rules Empty
broadcastTables (*) Collection<String> Broadcast table rules Empty
defaultDatabaseShardingStrategy (?) ShardingStrategyConfiguration Default database sharding strategy Not sharding
defaultTableShardingStrategy (?) ShardingStrategyConfiguration Default table sharding strategy Not sharding
defaultKeyGenerateStrategy (?) KeyGeneratorConfiguration Default key generator Snowflake
defaultAuditStrategy (?) ShardingAuditStrategyConfiguration Default key auditor DML_SHARDING_CONDITIONS
defaultShardingColumn (?) String Default sharding column name None
shardingAlgorithms (+) Map<String, AlgorithmConfiguration> Sharding algorithm name and configurations None
keyGenerators (?) Map<String, AlgorithmConfiguration> Key generate algorithm name and configurations None
auditors (?) Map<String, AlgorithmConfiguration> Sharding audit algorithm name and configurations None

Sharding Table Configuration

Class name: org.apache.shardingsphere.sharding.api.config.ShardingTableRuleConfiguration

Attributes:

Name DataType Description Default Value
logicTable String Name of sharding logic table -
actualDataNodes (?) String Describe data source names and actual tables, delimiter as point.
Multiple data nodes split by comma, support inline expression		 Broadcast table or databases sharding only
databaseShardingStrategy (?) ShardingStrategyConfiguration Databases sharding strategy Use default databases sharding strategy
tableShardingStrategy (?) ShardingStrategyConfiguration Tables sharding strategy Use default tables sharding strategy
keyGenerateStrategy (?) KeyGeneratorConfiguration Key generator configuration Use default key generator
auditStrategy (?) ShardingAuditStrategyConfiguration Sharding audit strategy configuration Use default auditor

Sharding Auto Table Configuration

Class name: org.apache.shardingsphere.sharding.api.config.ShardingAutoTableRuleConfiguration

Attributes:

Name DataType Description Default Value
logicTable String Name of sharding logic table -
actualDataSources (?) String Data source names.
Multiple data nodes split by comma		 Use all configured data sources
shardingStrategy (?) ShardingStrategyConfiguration Sharding strategy Use default sharding strategy
keyGenerateStrategy (?) KeyGeneratorConfiguration Key generator configuration Use default key generator

Sharding Strategy Configuration

Standard Sharding Strategy Configuration

Class name: org.apache.shardingsphere.sharding.api.config.strategy.sharding.StandardShardingStrategyConfiguration

Attributes:

Name DataType Description
shardingColumn String Sharding column name
shardingAlgorithmName String Sharding algorithm name

Complex Sharding Strategy Configuration

Class name: org.apache.shardingsphere.sharding.api.config.strategy.sharding.ComplexShardingStrategyConfiguration

Attributes:

Name DataType Description
shardingColumns String Sharding column name, separated by commas
shardingAlgorithmName String Sharding algorithm name

Hint Sharding Strategy Configuration

Class name: org.apache.shardingsphere.sharding.api.config.strategy.sharding.HintShardingStrategyConfiguration

Attributes:

Name DataType Description
shardingAlgorithmName String Sharding algorithm name

None Sharding Strategy Configuration

Class name: org.apache.shardingsphere.sharding.api.config.strategy.sharding.NoneShardingStrategyConfiguration

Attributes: None

Please refer to Built-in Sharding Algorithm List for more details about type of algorithm.

Distributed Key Strategy Configuration

Class name: org.apache.shardingsphere.sharding.api.config.strategy.keygen.KeyGenerateStrategyConfiguration

Attributes:

Name DataType Description
column String Column name of key generate
keyGeneratorName String key generate algorithm name

Please refer to Built-in Key Generate Algorithm List for more details about type of algorithm.

Sharding audit Strategy Configuration

Class name：org.apache.shardingsphere.sharding.api.config.strategy.audit.ShardingAuditStrategyConfiguration

Attributes：

Name DataType Description
auditorNames Collection<String> Sharding audit algorithm name
allowHintDisable Boolean Enable or disable sharding audit hint

Please refer to Built-in Sharding Audit Algorithm List for more details about type of algorithm.

Procedure

  1. Create an authentic data source mapping relationship, with key as the logical name of the data source and value as the DataSource object.
  2. Create the sharding rule object ShardingRuleConfiguration, and initialize the sharding table objects—ShardingTableRuleConfiguration, the set of bound tables, the set of broadcast tables, and parameters like library sharding strategy and the database sharding strategy, on which the data sharding depends.
  3. Using the ShardingSphereDataSource method of calling the ShardingSphereDataSourceFactory subject to create the ShardingSphereDataSource.

Sample

public final class ShardingDatabasesAndTablesConfigurationPrecise implements ExampleConfiguration {
    
    @Override
    public DataSource getDataSource() throws SQLException {
        return ShardingSphereDataSourceFactory.createDataSource(createDataSourceMap(), Collections.singleton(createShardingRuleConfiguration()), new Properties());
    }
    
    private ShardingRuleConfiguration createShardingRuleConfiguration() {
        ShardingRuleConfiguration result = new ShardingRuleConfiguration();
        result.getTables().add(getOrderTableRuleConfiguration());
        result.getTables().add(getOrderItemTableRuleConfiguration());
        result.getBindingTableGroups().add(new ShardingTableReferenceRuleConfiguration("foo", "t_order, t_order_item"));
        result.getBroadcastTables().add("t_address");
        result.setDefaultDatabaseShardingStrategy(new StandardShardingStrategyConfiguration("user_id", "inline"));
        result.setDefaultTableShardingStrategy(new StandardShardingStrategyConfiguration("order_id", "standard_test_tbl"));
        Properties props = new Properties();
        props.setProperty("algorithm-expression", "demo_ds_${user_id % 2}");
        result.getShardingAlgorithms().put("inline", new AlgorithmConfiguration("INLINE", props));
        result.getShardingAlgorithms().put("standard_test_tbl", new AlgorithmConfiguration("STANDARD_TEST_TBL", new Properties()));
        result.getKeyGenerators().put("snowflake", new AlgorithmConfiguration("SNOWFLAKE", new Properties()));
        result.getAuditors().put("sharding_key_required_auditor", new AlgorithmConfiguration("DML_SHARDING_CONDITIONS", new Properties()));
        return result;
    }
    
    private ShardingTableRuleConfiguration getOrderTableRuleConfiguration() {
        ShardingTableRuleConfiguration result = new ShardingTableRuleConfiguration("t_order", "demo_ds_${0..1}.t_order_${[0, 1]}");
        result.setKeyGenerateStrategy(new KeyGenerateStrategyConfiguration("order_id", "snowflake"));
        result.setAuditStrategy(new ShardingAuditStrategyConfiguration(Collections.singleton("sharding_key_required_auditor"), true));
        return result;
    }
    
    private ShardingTableRuleConfiguration getOrderItemTableRuleConfiguration() {
        ShardingTableRuleConfiguration result = new ShardingTableRuleConfiguration("t_order_item", "demo_ds_${0..1}.t_order_item_${[0, 1]}");
        result.setKeyGenerateStrategy(new KeyGenerateStrategyConfiguration("order_item_id", "snowflake"));
        return result;
    }
    
    private Map<String, DataSource> createDataSourceMap() {
        Map<String, DataSource> result = new HashMap<>();
        result.put("demo_ds_0", DataSourceUtil.createDataSource("demo_ds_0"));
        result.put("demo_ds_1", DataSourceUtil.createDataSource("demo_ds_1"));
        return result;
    }
}