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The Next_Item_Type()
Function
Oracle Tips by
Burleson
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The Next_Item_Type() function is used when unpacking a pipe
that can contain different types of values in the same positions. For
instance, a message might contain either a company name or a company
ID number in the same position. Depending on the value returned from
this function, the next portion of the message will be placed into a
character or number variable.
This function returns an integer value that indicates the datatype
of the next section of the message. These values are listed in Table
9.2.
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Table 9.2 Return values for the Next_Item_Type()
function. |
|
Return Value |
Datatype Of Next Message Section |
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0 |
There are no more values in the message |
|
6 |
number |
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9 |
varchar2 |
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11 |
ROWID |
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12 |
date |
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23 |
raw |
This function does not have any parameters.
The Pack_Message() Procedure
The Pack_Message() procedure is used to add information to a
message. The procedure is overloaded. The different implementations of
the procedure are as follows:
PROCEDURE Pack_Message (item IN varchar2)
PROCEDURE Pack_Message (item IN date)
PROCEDURE Pack_Message (item IN number)
PROCEDURE Pack_Message (item IN raw)
PROCEDURE Pack_Message (item IN ROWID)
Each implementation of this procedure is designed to add data of a
specific type to the message that will be sent over the pipe.
The Purge() Procedure
The Purge() procedure is used to completely empty the pipe,
thus freeing the memory used by the pipe when it is removed from the
SGA. Pipes are not removed from the SGA if they contain messages.
Therefore, it is critical that unnecessary pipes are emptied using
this procedure.
The procedure accepts a single parameter:
PROCEDURE Purge (pipename IN varchar2)
The pipename parameter holds the name of an existing pipe.
This procedure empties the pipe by calling the Receive_Message()
function repeatedly. Therefore, the values in the local buffer will
probably change if you use the Purge() procedure.
This is an excerpt from the book "High Performance Oracle
Database Automation" by Jonathan Ingram and Donald K.
Burleson, Series Editor. |
