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2.16 QUERY TRIGGER EVENTS AND MESSAGE DEFINITIONS

These are the trigger event types associated with queries:

a) a need occurs for immediate access to data that may be available from another application, this may be an initial request for data or a continuation

b) a need occurs for deferred access to data that may be available from another application

Where an original-style query is involved, these trigger events are served by the query message (QRY). When display data is involved, these trigger events are served by the Query (QRY) and Display Response (DSR) and General Acknowledgment (ACK) messages. When the query is for record-oriented data, the QRY message is used, but the response message is specific to a functional area. Record-oriented queries are described in detail in the relevant application chapters. Display-oriented response are described in detail in this chapter.

Although the query message of an event replay message is described in detail in this chapter, event replay response messages will be described in detail in the relevant application chapters.

Where an Embedded Query Language query is involved, these trigger events are served by the Embedded Query Language query (EQQ).

Where a virtual table query is involved, these trigger events are served by the Virtual Table Query (VQQ).

Where a stored procedure request is involved, these trigger events are served by the Stored Procedure request (SPQ) message.

For each of these query messages, one of the following response messages is used.

When display data is involved, these queries are responded to with the Display Response (DSR) message.

When tabular data is involved, these queries are responded to with the Tabular Data Response (TBR).

Where an event replay query is involved, these trigger events are served by the Event Replay Query (ERQ) and the Event Replay Response (RQQ) messages.

Where an original QRY query message is used to request record-oriented data, the response message is specific to a functional area. Application-segment-record-oriented queries are described in other chapters (3-8).

Display-oriented, tabular response messages, and event replay response messages are described here.

Each trigger event is listed below, with the applicable form of message exchange.

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