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# Using Data Constructs

StreamBase provides components called data constructs that store information used by associated StreamBase operators.

The data constructs in the table appear in the Data Constructs drawer of the Palette view in StreamBase Studio. Click the construct's name or icon in the table to open the topic page for that construct.

Icon | Operator | Description
--- | --- | ---
| Query Table | A table structure in an EventFlow module for storing tuple values outside of a stream, which allows the application to share data and maintain state. One or more Query operators can write to or read from an associated Query Table. Query Tables can be declared to reside in Java heap memory, on disk, or in transactional memory. Query Tables can reside in a module and can be accessed from outside the module.
| JDBC Table | Connects an EventFlow module to a JDBC database. A Query operator can then query the JDBC database to maintain state and use its data in the application.

To associate a Query operator with a Query Table or JDBC Table, draw an arc between the bottom port of the operator and the top port of the related data construct.

A data construct can be associated with multiple operators, but an operator can be associated with only one data construct.