# Variables in Aurora PostgreSQL Limitless Database
<a name="limitless-reference.variables"></a>

You can use the following variables to configure Aurora PostgreSQL Limitless Database.

**rds\$1aurora.limitless\$1active\$1shard\$1key**  
Sets a single shard key while querying the database, causing all `SELECT` and DML queries to be appended with the shard key as a constant predicate. For more information, see [Setting an active shard key](limitless-query.single-shard.md#limitless-query.single-shard.active).

**rds\$1aurora.limitless\$1create\$1table\$1collocate\$1with**  
Set this variable to a specific table name to collocate newly created tables with that table. For more information, see [Creating limitless tables by using variables](limitless-creating-config.md).

**rds\$1aurora.limitless\$1create\$1table\$1mode**  
Sets the table creation mode. For more information, see [Creating limitless tables by using variables](limitless-creating-config.md).

**rds\$1aurora.limitless\$1create\$1table\$1shard\$1key**  
Set this variable to an array of column names to use as shard keys. For more information, see [Creating limitless tables by using variables](limitless-creating-config.md).

**rds\$1aurora.limitless\$1explain\$1options**  
What to include in the `EXPLAIN` output. For more information, see [EXPLAIN](limitless-reference.DML-limitations.md#limitless-reference.DML-limitations.EXPLAIN).