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table reference property (JSDO)
table reference property (JSDO)
A property on a JSDO that has the name of a temp-table mapped by the Mobile
resource for which the current JSDO is created. Its value is a reference (table
reference) to the temp-table object in JSDO local storage. This temp-table object
provides access to the working record, if defined, of the temp-table. If a Mobile
resource maps a ProDataSet, its JSDO provides one table reference for every
temp-table in the ProDataSet.
Data type: Temp-table object reference in JSDO local storage
Access: Read-only
Applies to: progress.data.JSDO class
In syntax wherever a table reference can be used, table-ref represents the name of
the property containing the table reference. A referenced temp-table object provides
the following properties:
• record property— A reference to a JSRecord object that has the data for the
working record of the temp-table through a data property. If no working record is
defined for the temp-table, the record property is null.
• field reference property — A property on the temp-table object that has the
name of a field (as defined in the temp-table schema) and the value for that field
in the working record, also referred to as a field reference. In syntax wherever a
field reference can be used, field-ref represents the name of the property
containing the field reference. A temp-table object provides one field reference for
each field defined in the original temp-table. If no working record is defined, all field
references are null, except when fields are referenced on the data property of a
JSRecord object reference.
Caution: Never write directly to a field-ref using this record property or any
JSRecord object reference; in this case, use field-ref only to read the
data. Writing to data using such a reference does not mark the record for
update when calling the saveChanges( ) method. To mark a record for
update, you must assign a field value either by setting a
jsdo.table-ref.field-ref for a working record or by calling the
assign( ) method on a valid table-ref or JSRecord object reference.
You can therefore reference the field values in the working record of a given table
reference using either the JSRecord object returned by its record property or its field
references. The field references provide a convenient way to access table fields that is
similar to how you reference table fields in ABL. The record property provides an
alternative way to access table fields, especially one that has the same name as a
property or method of a JSDO that you can invoke from a table reference.
For example, the following code fragment shows two different ways to access the
CustNum field of a record added to a customer temp-table provided by a resource
ProDataSet:
var dataSet = new Progress.data.JSDO( 'CustomerOrderDS' );
dataSet.customer.add();
alert(dataSet.customer.record.data.CustNum);
alert(dataSet.customer.CustNum);
254 OpenEdge ® Development: Mobile Applications