DB_READ_BLOB and DBS_READ_BLOB actions

Declaration

DB_READ_BLOB handleIdent_Int, lobColNameIdent_Str, lobFileNameIdent_Str, retCodeIdent_Int, idKeyIdent [ORAHINT hintIdent_Str]
 
DB_READ_BLOB handleIdent_Int, lobColNameIdent_Str, lobFileNameIdent_Str, retCodeIdent_Int WHERE strExpression_Str [ORAHINT hintIdent_Str]
 
DBS_READ_BLOB dbObjIdent, lobColNameIdent_str, lobFileNameIdent_Str, retCodeIdent_Int, idKeyIdent [TRANS transHandle_Int] [ORAHINT hintIdent_Str]
 
DBS_READ_BLOB dbObjIdent, lobColNameIdent_str, lobFileNameIdent_Str, retCodeIdent_Int WHERE strExpression_Str [TRANS transHandle_Int] [ORAHINT hintIdent_Str]

Parameters

handleIdent_Int	in	Identifier of Int type (handle) of the connection to the database (DB_CONNECT).
lobColNameIdent_Str	in	Name of a column of LOB type in the table.
lobFileNameIdent_Str	in	Name of a file, where the LOB type record read is to be written.
transHandle_Int	in	Identifier of the Connection to the database.
idKeyIdent	in	Identification key determining the row (if the key consists of several columns, idKeyIdent is a structure of the same type as the table - just values of key columns are to be taken into account).
strExpression_Str	in	Expression of String type, that defines the table row read.
dbObjIdent	in	Reference to an object of Database table type.
retCodeIdent_Int	out	Return code of Int type - action success.
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.

Description

The action allows to read one record of LOB type from a table in a database. The table is defined either by the parameter handleIdent_Int, which was got by previous calling the action DB_CONNECT or by the identifier dbObjectIdent representing an object of Database Table type. The 3rd and 4th types of the declarations is concerned to DBS actions, which do not require the explicit actions to open and close the database (DB_CONNECT and DB_DISCONNECT). Also it is possible to use the identifier running transaction transHanlde_Int gained by previous calling the action DB_TRANS_OPEN.
The read record of LOB type is written into a file, which name is given in the parameter lobFileNameIdent_Str. If the file already exists, then will be overwritten.
A value of the identifier lobColNameIdent_Str defines a name of the column, which type is LOB and will be read.

A row, which will be read, can be defined:

Using the parameter idKeyIdent. An identification key must be defined in the configuration of an object of Database table type. Then a row, with a value matching the given identification key, will be found in the table.
By a value of the expression strExpression_Str, that represents a clause WHERE for the SQL command SELECT executing a selection from the table.

The parameter retCodeIdent_Int returns the attribute _ERR_NO_ERROR - action success, or:

_ERR_FILE_ERROR - an error occurred during operation with the file.
_ERR_NO_DATA - if the record in the database is NULL.
Other default error codes.

Related pages:

Script actions

Strom stránky

DB_READ_BLOB

DB_READ_BLOB and DBS_READ_BLOB actions