ShardingKey (Java SE 25 & JDK 25)
Description: declaration: module: java.sql, package: java.sql, interface: ShardingKey
Keywords: java.sql.ShardingKey interface

# Interface ShardingKey

public interface ShardingKey
Interface used to indicate that this object represents a Sharding Key. A `ShardingKey` instance is only guaranteed to be compatible with the data source instance that it was derived from. A `ShardingKey` is created using `ShardingKeyBuilder`.

The following example illustrates the use of `ShardingKeyBuilder` to create a `ShardingKey`:

        DataSource ds = new MyDataSource();
        ShardingKey shardingKey = ds.createShardingKeyBuilder()
                              .subkey("abc", JDBCType.VARCHAR)
                              .subkey(94002, JDBCType.INTEGER)
                              .build();

A `ShardingKey` may also be used for specifying a `superShardingKey`. Databases that support composite Sharding may use a `superShardingKey` to specify a additional level of partitioning within the Shard.

The following example illustrates the use of `ShardingKeyBuilder` to create a `superShardingKey` for an eastern region with a `ShardingKey` specified for the Pittsburgh branch office:

        DataSource ds = new MyDataSource();
        ShardingKey superShardingKey = ds.createShardingKeyBuilder()
                              .subkey("EASTERN_REGION", JDBCType.VARCHAR)
                              .build();
        ShardingKey shardingKey = ds.createShardingKeyBuilder()
                              .subkey("PITTSBURGH_BRANCH", JDBCType.VARCHAR)
                              .build();
        Connection con = ds.createConnectionBuilder()
                              .superShardingKey(superShardingKey)
                              .shardingKey(shardingKey)
                              .build();

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