Chapter 5: Real Time Data Functions

msgpublish

Description

Provides a SQL interface to publish messages to topics.

Syntax

 msgpublish_call::=msgpublish
       (message_body, subscription_name [options_and_properties)
 options_and_properties::=
       [option_clause] [properties_clause]
 option_clause::=[,] option option_string]
 properties_clause::=[,]message property option_string
 message_body::=
      scalar_expression
 | (select_for_xml)

Parameters

message_body: The message you are sending. The message body can contain any string of characters. It can be binary data, character data, or SQLX data.

subscription_name: Name of the subscription to which you are publishing messages.

option_string

The general format of an option_string is specified in the section option_string—general format.

The options you can specify for msgsend are in Table 5-1:

Table 5-5: Options for **msgpublish**
Option	Value	Default	Comments
schema	no yes “user_schema”	no	user_schema is a user-supplied schema describing the message_body. ‘no’ means that no schema is generated and sent out as part of the message. ‘yes’ means that Adaptive Server generates an XML schema for the message. ‘yes’ is only meaningful in a message_body that uses the select_for_xml parameter. select_for_xml generates a SQLX-formatted representation of the SQL result set. The generated XML schema is a SQLX-formatted schema that describes the result set document. The schema is included in the message as ASE_MSGBODY_SCHEMA property.
type	text \| bytes	text	The message type to send.

option_string

The general format of an option_string is specified in the section option_string—general format.

The options you can specify for msgpublish are in Table 5-5.

properties_clause

Is either an option_string or one of the options listed in Table 5-6. The options described in Table 5-6 are set as a property in the message header or message properties, as indicated in the disposition column of the table. The option value is the property value.

Property names are case sensitive.

If you use a property not listed in Table 5-2, it is set as a property in the message properties of the message sent.

**Table 5-6: Option values for properties of msgpublish**
Option	Values	Default	Disposition	Comments
mode	persistent or nonpersistent	persistent	header	If the mode is persistent, the message is backed by the JMS provider, using stable storage. If the messaging provider crashes before the message can be consumed, the message is lost, unless mode is set to persistent. If the mode is nonpersistent, and the messaging providercrashes, you may lose a message before it reaches the desired destination.
ttl	0 – (2⁶³-1)	0	header	ttl refers to time-to-live on the messaging bus. Adaptive Server is not affected by this. Expiry information, which is the duration of time during which the message is valid, in milliseconds. For instance, 60 means that the life of the message is 60 milliseconds. A value of 0 means that the message does not expire.
priority	1 to 10	4	header	The behavior of priority is controlled by the underlying message bus. The values mentioned here apply to TIBCO_JMS. Priorities from 0 to 4 are normal; priorities from 5 to 9 are expedited.
correlation	string	none	header	Client applications set correlation IDs to link messages together. Adaptive Server sets the correlation ID the application specifies.
replyqueue replytopic	A string containing a queue_name A string containing a topic_name	none none	header header	The value of queue_name or topic_name must be syb_temp. The type of the temporary destination, queue or topic, depends on whether you specify replyqueue or replytopic. Only the option listed last is used. Adaptive Server creates a temporary destination and sends information related to the newly created temporary destination as a part of the header information.

scalar_expression

If a message is a SQL scalar_expression, it can be of any datatype.

If the type option is not specified, the message type is text if the scalar_expression evaluates to a character datatype; otherwise the message type is bytes.

If the datatype of the scalar_expression is not character, it is converted to varbinary using the normal SQL rules for implicit conversion. The binary value of the datatype is included in the message according to the byte ordering of the host machine.

select_for_xml: A select expression that specifies a for xml clause.

Examples

Example 1

To publish messages, a subscription must be defined on the server to which the client is connected:

sp_msgadmin ’register’, ’subscription’,’subscription_1’,
     ’my_jms_provider?topic=topic.sample,user=user1,password=pwd’,
     ’Supplier=12345’,null, ’durable1’, ’client’

Example 2

Then the client server can publish a message to a specified subscription:

select msgpublish
     (’Sending order’, ’subscription_1’,
     MESSAGE PROPERTY ’Supplier=12345’)

Usage

The subscription_name must have been specified in a call to:
```
sp_msgadmin ’register’, ’subscription’
```
It should not be specified in a subsequent call to:
```
sp_msgadmin ’remove’, ’subscription’
```

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