= Generic Database Messages: Using modelglue.!GenericRead =

When this message is broadcast, the !DataController will attempt to read a specific record from a given table.

This message is configured by using the following <argument> tags:

  1. Object (Required) - The name of the table from which to read.
  1. !RecordName (Optional) - The name of the viewstate value to set the resultant record into. Defaults to Object & "Record".
  1. Criteria (Optional) - A list of viewstate values to use as filters. Any value listed whose name matches a column in the target table will be used as a filter in the query's WHERE clause. This will most often be set to a list of the table's primary keys. If left empty, a new record will be created.

== Examples ==

=== A Basic Generic Read ===

To perform a basic read on a Contact table, the following <message> tag could be added to an <event-handler>:

{{{
<message name="modelglue.GenericRead">
    <argument name="object" value="Contact" />
</message>
}}}

A View could then <cfdump> the record by performing the following code:

{{{
<cfdump var="#viewstate.getValue("ContactRecord")#" />
}}}

Note: Because no criteria were specified, this would return a new, empty record.

=== Customizing the Viewstate value name ===

To perform a basic read on a Contact table and set it into a specific value in the Viewstate, the following <message> tag could be added to an <event-handler>:

{{{
<message name="modelglue.GenericRead">
    <argument name="object" value="Contact" />
    <argument name="recordName" value="myContact" />
</message>
}}}

A View could then <cfdump> the record by performing the following code:

{{{
<cfdump var="#viewstate.getValue("myContact")#" />
}}}

Note: Because no criteria were specified, this would return a new, empty record.

=== Reading a Specific Record ===

To perform a basic read of a Contact record that would filter on the viewstate's current !ContactId value, the following <message> tag could be added to an <event-handler>:

{{{
<message name="modelglue.GenericRead">
    <argument name="object" value="Contact" />
    <argument name="criteria" value="ContactId" />
</message>
}}}

Assuming an event-handler name of "contact.read", visiting the event handler with the following URL would result in reading a contact with a !ContactId value of 42.

index.cfm?event=contact.read&contactId=42