Assignment (=) statement

Database or temp-table field

Variable scoped to the current procedure, user-defined function, or method of a class or an accessible class-based variable data member, including a subscripted or unsubscripted array variable

Parameter defined for the current procedure, user-defined function, or method of a class, including a subscripted or unsubscripted array parameter

Writable class-based or COM property, including a subscripted or unsubscripted array property

Writable handle attribute (such as PRIVATE-DATA)

Writable system handle (such as CURRENT-WINDOW)

ABL syntax that specifies a keyword-driven assignment statement (such as the PROPATH statement, SUBSTRING statement, or similar statement)

Check the ERROR-STATUS:ERROR attribute to see if the AVM raised the ERROR condition.

Check if the ERROR-STATUS:NUM-MESSAGES attribute is greater than zero to see if the AVM generated error messages. ABL handle methods used in a block without a CATCH end block treat errors as warnings and do not raise ERROR, do not set the ERROR-STATUS:ERROR attribute, but do add messages to the ERROR-STATUS system handle. Therefore, this test is the better test for code using handle methods without CATCH end blocks. ABL handle methods used in a block with a CATCH end block raise ERROR and add messages to the error object generated by the AVM. In this case, the AVM does not update the ERROR-STATUS system handle.

Use ERROR-STATUS:GET-MESSAGE( message-num ) to retrieve a particular message, where message-num is 1 for the first message.

NO-ERROR does not suppress errors that raise the STOP or QUIT condition.

A CATCH statement, which introduces a CATCH end block, is analogous to a NO-ERROR option in that it also suppresses errors, but it does so for an entire block of code. It is different in that the error messages are contained in a class-based error object (generated by the AVM or explicitly thrown), as opposed to the ERROR-STATUS system handle. Also, if errors raised in the block are not handled by a compatible CATCH block, ON ERROR phrase, or UNDO statement, then the error is not suppressed, but handled with the default error processing for that block type.

When a statement contains the NO-ERROR option and resides in a block with a CATCH end block, the NO-ERROR option takes precedence over the CATCH block. That is, an error raised on the statement with the NO-ERROR option will not be handled by a compatible CATCH end block. The error is redirected to the ERROR-STATUS system handle as normal.

If an error object is thrown to a statement that includes the NO-ERROR option, then the information and messages in the error object will be used to set the ERROR-STATUS system handle. This interoperability feature is important for those integrating code that uses the traditional NO-ERROR technique with the newer, structured error handling that features error objects and CATCH end blocks.

If field is an integer and expression is a decimal, the AVM rounds the value of the expression before assigning it. If field is a decimal and expression is a decimal, the AVM rounds the value of the expression to the number of decimal places defined for the field in the Data Dictionary, or defined or implied for a variable or temp-table field.

If field is an ABL array type (defined with EXTENT) and expression is not an array, and you do not identify a particular array element, the AVM stores expression in each element of the array. If you identify a particular element, the AVM stores expression in the specified array element.

If both field and expression are ABL array types, the AVM copies the data for all expression array elements into the corresponding elements of the field array. This is known as a deep copy.

An indeterminate array is one where the size of the EXTENT is not yet fixed. A determinate array is one where the EXTENT size is fixed. When deep copying one array to another, the following rules apply:

If both the array on the left-hand side and the right-hand side of the equation are determinate arrays, the EXTENT size must match or the AVM raises an error.

You cannot assign an indeterminate array to a determinate array.

You can assign any array to an indeterminate array, but you cannot assign a scalar value to an indeterminate array.

ABL allows you to assign ABL arrays and .NET array objects to each other. How an array assignment works between ABL and .NET arrays depends upon the array type of field (the target of the assignment) and the array type of expression (the source for the assignment). For more information, see the Data types reference entry.

If an assignment of one array to another encounters an error after some, but not all of the source array's elements are retrieved, none of the target's elements are updated.

If expression is an ABL handle-based object (for example, a temp-table, ProDataSet, widget, or socket), field must be a temp-table field, variable, or other ABL data element defined as a compatible handle. In this case, the AVM assigns only the handle of the ABL handle-based object to field, not the entire object and its contents.

If you assign a value to a database field, any ASSIGN trigger associated with that field executes at the end of the assignment statement (after any index changes are made). If the trigger raises ERROR, the assignment fails and the database changes are undone.

You can embed an assignment in a SET or UPDATE statement.

For multiple assignments, use the ASSIGN statement. This is more efficient than multiple assignment statements.

If field is a handle, the expression on the right-hand-side must also evaluate to a handle value that is specified using an appropriate reference to a handle-based object handle. For more information on object handle references, see the Handle Attributes and Methods Reference.

You can assign DATE, DATETIME, and DATETIME-TZ data. When the data type expression on the left side of the assignment statement contains more information than the data type expression on the right side provides (for example, datetime-tz = date where a DATETIME-TZ value contains more information than a DATE value), the time value defaults to midnight and the time zone is calculated using SESSION:TIMEZONE when that attribute is in use. If the attribute is not in use, the value defaults to the session's timezone. When the data type expression on the left side of the assignment statement contains less information than the data type expression on the right side provides (for example, date = datetime-tz where a DATE value contains less information than a DATETIME-TZ value), the AVM converts the DATETIME-TZ value to the local date and time of the session, then drops the time and time zone.

Starting with Version 9.1, you can assign RAW values to MEMPTR variables and MEMPTR values to RAW variables. If the target variable is a RAW data type, the AVM re-sizes the target variable, if necessary, so that after the assignment is the same size as the source. Note that after the assignment (whether RAW = MEMPTR or MEMPTR = RAW), the target variable has a copy of the memory associated with the source—each variable has an independent copy of the data.

You can assign large object data from one BLOB or MEMPTR to another, and from one CLOB, LONGCHAR, or CHARACTER to another. You cannot assign large object data between BLOBs and CLOBs or MEMPTRs and LONGCHARs. You can accomplish this, indirectly, by using the COPY-LOB statement. For more information, see the COPY-LOB statement reference entry.

When you assign the Unknown value (?) to a BLOB or CLOB field, the AVM deletes any associated object data.

If expression is a solitary invocation of the NEW function (classes), this statement represents and conforms to the rules specified for the NEW statement.

If expression evaluates to an object reference value, field must also be a data element defined as a class or interface type that is type-compatible with expression according to the rules for assigning references to class instances defined for the NEW statement. For more information, see the NEW statement reference entry. Thus, you can assign one object reference variable to another object reference variable when the destination object reference (on the left side of the assignment) is defined for the same class, a super class, or an interface of the object reference being assigned (on the right side of the assignment). The destination object reference retains its defined class or interface type for compilation. However, following its assignment, at run time, the destination represents the sublcass of field (or the class that implements the interface specified by field) that is defined by expression.

Although you can assign an object reference to a temp-table field defined as a Progress.Lang.Object class type, you cannot assign an object reference to a field in a database table. For more information, see OpenEdge Development: Object-oriented Programming.