4D v16.3

DOCUMENT TO BLOB

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4D v16.3
DOCUMENT TO BLOB

DOCUMENT TO BLOB 


 

DOCUMENT TO BLOB ( document ; blob {; *} ) 
Parameter Type   Description
document  String in Name of the document
blob  BLOB in BLOB field or variable to receive the document
in Document contents
Operator in *** Obsolete, do not use ***

DOCUMENT TO BLOB loads the whole contents of document into blob. You must pass the name of an existing document that is not already open, otherwise an error will be generated. To let the user choose the document to be loaded into the BLOB, use the command Open document and the process variable document (see Example).

Compatibility Note: The optional * (resource fork management in older versions of Mac OS) is no longer supported in 4D as of 4D v16. For more information, see the Deprecated and Removed Features manual.

Example  

You write an Information System that enables you to quickly store and retrieve documents. In a data entry form, you create a button that allows you to load a document into a BLOB field. The method for this button could be:

 $vhDocRef:=Open document("") ` Select the document of your choice
 If(OK=1) ` If a document has been chosen
    CLOSE DOCUMENT($vhDocRef` We don't need to keep it open
    DOCUMENT TO BLOB(Document;[YourTable]YourBLOBField` Load the document
    If(OK=0)
  ` Handle error
    End if
 End if

OK is set to 1 if the document is correctly loaded, otherwise OK is set to 0 and an error is generated.

  • If you try to load (into a BLOB) a document that does not exist or that is already open by another process or application, the appropriate File Manager error is generated.
  • An I/O error can occur if the document is locked, located on a locked volume, or if there is problem in reading the document.
  • If there is not enough memory to load the document, an error -108 is generated.

In each case, you can trap the error using an ON ERR CALL interruption method.



See also 

BLOB TO DOCUMENT
Open document

 
PROPERTIES 

Product: 4D
Theme: BLOB
Number: 525

The OK variable is changed by the commandThis command can be run in preemptive processesThis command has platform-specific behavior

 
HISTORY 

Created: 4D v6

 
TAGS 

Storing documents, Resource fork, Data fork, Document

 
ARTICLE USAGE

4D Language Reference ( 4D v16)
4D Language Reference ( 4D v16.1)
4D Language Reference ( 4D v16.2)
4D Language Reference ( 4D v16.3)