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 StreamBase application 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-memory, or on-disk. (Disk-based query tables are a feature that you can use only if your StreamBase license enables it.) Query Tables can reside in a module and can be accessed from outside the module.
Materialized Window A view of tuples passing through an input stream (unlike other data constructs, which do not have input streams). The view can be based on a fixed number of tuples, a time interval, or a field value. You can then directly query the data in the materialized window using a read-only Query operator.


The Materialized Window data construct remains available in StreamBase, but its use is discouraged. Materialized Windows may be superseded in a future release by a new feature with similar capabilities.

JDBC Table Connects a StreamBase application to a JDBC database. A Query operator can then query the JDBC database to maintain state and use its data in the application.
Lock Set A data construct associated with a pair of Lock and Unlock operators.

To associate a Query operator with a Query Table, Materialized Window, or JDBC Table, or to associate Lock and Unlock Operators with a Lock Set, 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.