Using the SQL Outbound Adapter

Default BehaviorCopy link to this section

Within a production, an outbound adapter is associated with a business operation that you create and configure. The business operation receives a message from within the production, looks up the message type, and executes the appropriate method. This method usually executes methods of the associated adapter.

The SQL outbound adapter (EnsLib.SQL.OutboundAdapter) provides settings that you use to specify the data source to connect to and any login details needed for that data source. It also provides methods to perform common SQL activities such as the following:

• Executing queries

• Executing stored procedures

• Performing inserts, updates, and deletes

Creating a Business Operation to Use the AdapterCopy link to this section

To create a business operation to use the EnsLib.SQL.OutBoundAdapter, you create a new business operation class. Later, add it to your production and configure it.

You must also create appropriate message classes, if none yet exist. See “Defining Ensemble Messages” in Developing Ensemble Productions.

The following list describes the basic requirements of the business operation class:

• Your business operation class should extend Ens.BusinessOperation.

• The ADAPTER parameter should equal EnsLib.SQL.OutboundAdapter.

• The INVOCATION parameter should specify the invocation style you want to use, which must be one of the following.

  • Queue means the message is created within one background job and placed on a queue, at which time the original job is released. Later, when the message is processed, a different background job will be allocated for the task. This is the most common setting.

  • InProc means the message will be formulated, sent, and delivered in the same job in which it was created. The job will not be released to the sender’s pool until the message is delivered to the target. This is only suitable for special cases.

• Your class should define a message map that includes at least one entry. A message map is an XData block entry that has the following structure:

  XData MessageMap
  {
  <MapItems>
    <MapItem MessageType="messageclass">
      <Method>methodname</Method>
    </MapItem>
    ...
  </MapItems>
  }
  

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• Your class should define all the methods named in the message map. These methods are known as message handlers. In general, these methods will refer to properties and methods of the Adapter property of your business operation.

• For other options and general information, see “Defining a Business Operation Class” in Developing Ensemble Productions.

The following example shows the general structure that you need:

Class ESQL.NewOperation1 Extends Ens.BusinessOperation 
{
Parameter ADAPTER = "EnsLib.SQL.OutboundAdapter";

Parameter INVOCATION = "Queue";

Method SampleCall(pRequest As Ens.Request, Output pResponse As Ens.Response) As %Status
{
  Quit $$$ERROR($$$NotImplemented)
}

XData MessageMap
{
<MapItems>
  <MapItem MessageType="Ens.Request">
    <Method>SampleCall</Method>
  </MapItem>
</MapItems>
}
}

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Creating Methods to Perform SQL OperationsCopy link to this section

When you create a business operation class for use with EnsLib.SQL.OutboundAdapter, typically your biggest task is writing message handlers, that is, methods to perform various SQL operations. In general, these methods will refer to properties and methods of the Adapter property of your business operation. For example:

 set tSC = ..Adapter.ExecuteUpdate(.numrows,sql)

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A method might look like the following.

/// Insert into NewCustomer table
Method Insert(pReq As ESQL.request, Output pResp As ESQL.response1) As %Status
{
 kill pResp
 set pResp=$$$NULLOREF

 set sql="insert into NewCustomer (Name,SSN,City,SourceID) values (?,?,?,?)"

 //perform the Insert
 set tSC = ..Adapter.ExecuteUpdate
   (.nrows,sql,pReq.Name,pReq.SSN,pReq.City,pReq.CustomerID)

 //create the response message
 set pResp=##class(ESQL.response1).%New()
 set pResp.AffectedRows=nrows

 if 'tSC write " failed ",tSC quit tSC
 quit 1
}

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To create these methods, you should become familiar with the methods and properties of the EnsLib.SQL.OutboundAdapter class. The chapter “Creating Adapter Methods for SQL” provides more detail about these tools.

Handling Multiple SQL Statements per MessageCopy link to this section

The adapter configuration is designed to deal with the simple case where the business operation executes one SQL statement per message it receives. If your business operation needs to execute multiple SQL statements for a given message, use the following style (or similar) in your OnMessage() method:

OnMessage(..)
{
    Set tStayConn=..Adapter.StayConnected
    Set ..Adapter.StayConnected=-1
 
    //... your ..Adapter SQL Operations here...
 
   Set ..Adapter.StayConnected=tStayConn
   If 'tStayConn&&..Adapter.Connected Do ..Adapter.Disconnect()
   Quit tSC
}

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Adding and Configuring the Business OperationCopy link to this section

To add your business operation to an Ensemble production, use the Management Portal to do the following:

1. Add an instance of your custom business operation class to the Ensemble production.

2. Enable the business operation.

3. Configure the adapter to communicate with a specific external data source. Specifically:

   • Specify the data source to which the adapter should connect

   • Use other common runtime settings for your production

4. Run the production.