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DB_UPDATE and DBS_UPDATE actions


Function
Modification of the given existing row (rows) in the database.
Declaration
 DB_UPDATE handleIdent_Int, rowIdent, retCodeIdent_Int [WHERE strExpression_Str [BINDIN varIdent1, varIdent2, ... ]] [ORAHINT hintIdent_Str] 

 DB_UPDATE handleIdent_Int, rowIdent, retCodeIdent_Int [WHERE strExpression_Str [BINDIN structRowIdent]] [ORAHINT hintIdent_Str] 

 DBS_UPDATE dbObjIdent, rowIdent, retCodeIdent_Int [WHERE strExpression_Str [BINDIN varIdent1, varIdent2, ... ]] [TRANS transHandle_Int] [ORAHINT hintIdent_Str] 

 DBS_UPDATE dbObjIdent, rowIdent, retCodeIdent_Int [WHERE strExpression_Str [BINDIN structRowIdent]] [TRANS transHandle_Int] [ORAHINT hintIdent_Str] 

 
or
 
DB_UPDATE handleIdent_Int, structIdent, retCodeIdent_Int [ORAHINT hintIdent_Str] 
 
  DBS_UPDATE dbObjIdent, structIdent, retCodeIdent_Int [TRANS transHandle_Int] [ORAHINT hintIdent_Str] 

Parameters
handleIdent_Int in Identifier of Int type (handle) of the connection with the database (DB_CONNECT).
dbObjIdent in Reference to an object of Database table type.
rowIdent in One structure row identifier (a row to insert).
structIdent in Identifier of entire structure (the rows to insert).
retCodeIdent_Int out Return value of Int type - action success.
strExpression_Str in Expression of String type, which identifies modified rows. If the expression is parameterized, the keyword BINDIN and the values of parameters (structRowIdent or varIdent1, varIdent2, ...) are mandatory.
varIdent1,
varIdent2, ...
in List of objects, constants or local variables, which will specify the values of parameters of parameterized SQL expression strExpression_Str.
structRowIdent in Reference to a row of local variable of Record type or to a row of structured variable. The row's values will specify the values of parameters of parameterized SQL expression strExpression_Str.
transHadle_Int in Identifier of the Connection to the database.
hintIdent_Str in Expression of String type that defines Oracle SQL hint. It is used as an instruction for the performance optimizer of SQL command. The value is used without the opening and terminating characters /*+ <orahint> */.
The example is mentioned here.

Return code
The value of the parameter transHandle_Int. See the table of error codes. It is possible to get extended error information.
Description
The database must be opened with the access _DB_MODIFY. Analogous to the action DB_READ (DBS_READ), modified rows may be determined by two ways: 
  1. Setting the key item in a structure row (rowIdent) or in the entire structure (structIdent). The setting must be performed before the action DB_UPDATE. The item must be signed as the key during the definition of an object of Database type. Then in the database,  there is found a row which key item value is equal to the key item and is modified. The inserted row or structure must contain a proper type of structure. Each item of the inserted row must contain a valid value.
  2. The value of the expression strExpression_Str which represents
    WHERE
    clause for the SQL command UPDATE executing a database change. In this case, a key item value is not used.

The advantage of the action DBS_UPDATE during the work with a table is the possibility to leave out its opening and closing (simpler notation).

For D2000 v5.00: A disadvantage of the action DBS_UPDATE is in speed. Each DBS_UPDATE call results in necessity to open and close the database in DBManager - it can be a time-consuming operation and it is a comparatively nonstandard method in term of databases.
The need to open and close the database may be eliminated in the scope of transaction processing so that the command is followed by the parameter

TRANS
.

For D2000 v6.00 and higher: DBManager optimization (connection recycling, predefined connections) causes, that the action DBS_UPDATE is executes as quick as the action DB_UPDATE and as moreover there is saved a time required for execution of the action  DB_CONNECT to open the database.

The need to open and close the database may be eliminated in the scope of transaction processing so that the command is followed by the parameter

TRANS
.



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