Verifies that a record complies with mandatory
field and unique index definitions. It clears the record from the
buffer and unites it to the database if it has been changed.
Syntax
RELEASE record[ NO-ERROR ]
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record
- The name of a record buffer.
To use RELEASE with a record
in a table defined for multiple databases, you must qualify the
record's table name with the database name. See the Record phrase reference
entry for more information.
- NO-ERROR
- Suppresses ABL errors or error messages that would otherwise
occur and diverts them to the ERROR-STATUS system handle. If an error occurs, the action of the statement
is not done and execution continues with the next statement. If
the statement fails, any persistent side-effects of the statement
are backed out. If the statement includes an expression that contains
other executable elements, like methods, the work performed by these
elements may or may not be done, depending on the order the AVM
resolves the expression elements and the occurrence of the error.
For
the RELEASE statement, as an exception to the general rule, if a unique
index constraint is violated the NO-ERROR clause is ignored when
validating the record. An error is raised before any changes are saved
to the record to avoid damaging any indexes.
To check for
errors after a statement that uses the NO-ERROR option:
- 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.
If the statement does not include
the NO-ERROR option, you can use a CATCH end block to handle errors
raised by the statement.
Some other important usage notes
on the NO-ERROR option:
- 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.
Example
The
following example uses a browse widget to scan Customer records. Records
within the browse are read with NO-LOCK. If you choose the Update Customer
button, the CHOOSE trigger starts a transaction and applies an EXCLUSIVE-LOCK
to the Customer record. When you have completed any updates, the
procedure displays the new values in the browse widget and then executes
a RELEASE statement. This ensures that the lock is released when
the transaction ends.
r-rels.p
DEFINE VARIABLE methRtn AS LOGICAL NO-UNDO.
DEFINE VARIABLE curr-cust AS ROWID NO-UNDO.
DEFINE BUTTON upd-cust LABEL "Update Customer".
DEFINE BUTTON exit-app LABEL "Exit".
DEFINE QUERY seq-cust FOR customer.
DEFINE BROWSE brow-cust QUERY seq-cust
DISPLAY Customer.CustNum Customer.Name WITH 10 DOWN.
FORM
upd-cust exit-app SKIP(1)
brow-cust
WITH FRAME main-frame.
FORM
Customer EXCEPT Customer.Comments
WITH FRAME curr-frame COLUMN 40.
OPEN QUERY seq-cust FOR EACH Customer.
ON VALUE-CHANGED OF brow-cust DO:
DISPLAY Customer EXCEPT Customer.Comments
WITH FRAME curr-frame SIDE-LABELS.
curr-cust = ROWID(Customer).
END.
ON CHOOSE OF upd-cust DO: /* TRANSACTION */
FIND Customer WHERE ROWID(Customer) = curr-cust EXCLUSIVE-LOCK.
UPDATE Customer WITH FRAME cust-frame VIEW-AS DIALOG-BOX
TITLE "Customer Update".
methRtn = brow-cust:REFRESH().
DISPLAY Customer EXCEPT Customer.Comments
WITH FRAME curr-frame SIDE-LABELS.
RELEASE Customer.
END.
ENABLE ALL WITH FRAME main-frame.
APPLY "VALUE-CHANGED" TO brow-cust.
PAUSE 0 BEFORE-HIDE.
WAIT-FOR CHOOSE OF exit-app OR WINDOW-CLOSE OF DEFAULT-WINDOW.
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If you omit the RELEASE statement in this example,
the EXCLUSIVE-LOCK is downgraded to a SHARE-LOCK at the end of the
transaction. This prevents other uses from updating that record.
The SHARE-LOCK is released when you change the iteration of the
browse.
Notes
- An
ERROR occurs if the validation of the record fails. This can happen
only with newly created records.
- If a record has been modified, the RELEASE statement causes
a WRITE event and fires any related WRITE trigger to execute. All
WRITE triggers execute before the record is actually written. If
a WRITE trigger fails (or executes a RETURN statement with the ERROR option),
the corresponding record is not written or released and the ERROR
condition is raised for the RELEASE statement.
- See OpenEdge Getting Started: ABL Essentials for
more information on transactions.