IBM BPM, V8.0.1, All platforms > Programming IBM BPM > Developing client applications for BPEL processes and tasks > Queries on BPEL process and task data

Business Process Choreographer EJB query API

You can use the query method or the queryAll method of the service API to retrieve stored information about BPEL processes and tasks. However, it is generally preferable to use the query table API instead.

The query method can be called by all users, and it returns the properties of the objects for which work items exist. The queryAll method can be called only by users who have one of the following Java™ EE roles: BPESystemAdministrator, TaskSystemAdministrator, BPESystemMonitor, or TaskSystemMonitor. This method returns the properties of all the objects that are stored in the database.

All API queries are mapped to SQL queries. The form of the resulting SQL query depends on the following aspects:

• Whether the query was invoked by someone with one of the Java EE roles.

• The objects that are queried. Predefined database views are provided for you to query the object properties.

• The insertion of a from clause, join conditions, and user-specific conditions for access control.

You can include both custom properties and variable properties in queries. If you include several custom properties or variable properties in your query, this results in self-joins on the corresponding database table. Depending on your database system, these query() calls might have performance implications.

You can also store queries in the Business Process Choreographer database using the createStoredQuery method. You provide the query criteria when you define the stored query. The criteria are applied dynamically when the stored query runs, that is, the data is assembled at run time. If the stored query contains parameters, these are also resolved when the query runs.

For more information on the Business Process Choreographer APIs, see the Javadoc in the com.ibm.bpe.api package for process-related methods and in the com.ibm.task.api package for task-related methods.

• Syntax of the API query method
  The syntax of the Business Process Choreographer API queries is similar to SQL queries. A query can include a select clause, a where clause, an order-by clause, a skip-tuples parameter, a threshold parameter and a time-zone parameter.
• User-specific access conditions
  User-specific access conditions are added when the SQL SELECT statement is generated from the API query. These conditions guarantee that only those objects are returned to the caller that satisfy the condition specified by the caller and to which the caller is authorized.
• Examples of the query and queryAll methods
  These examples show the syntax of various typical API queries and the associated SQL statements that are generated when the query is processed.
• Manage stored queries
  Stored queries provide a way to save queries that are run often. The stored query can be either a query that is available to all users (public query), or a query that belongs to a specific user (private query).

Queries on BPEL process and task data

Related reference:
Database views for Business Process Choreographer