Bfile Class

The Bfile class defines the common properties of objects of type BFILE. A BFILE is a large binary file stored in an operating system file outside of the Oracle database. A Bfile object contains a logical pointer to a BFILE, not the BFILE itself.

Methods of the Bfile class enable you to perform specific tasks related to Bfile objects.

Methods of the ResultSet and Statement classes, such as getBfile() and setBfile(), enable you to access an SQL BFILE value.

The only methods valid on a NULL Bfile object are setName(), isNull(), and operator=().

An uninitialized Bfile object can be initialized by:

• The setName() method. The BFILE can then be modified by inserting this BFILE into the table and then retrieving it using SELECT ... FOR UPDATE. The write() method will modify the BFILE; however, the modified data will be flushed to the table only when the transaction is committed. Note that an insert is not required.

• Assigning an initialized Bfile object to it.

  See Also:

  In-depth discussion of LOBs in the introductory chapter of Oracle Database Application Developer's Guide - Large Objects,

Bfile()

Bfile class constructor.

Bfile();

Bfile(
   const Connection *connectionp);

Bfile(
   const Bfile &srcBfile);

connectionp

srcBfile

close()

Closes a previously opened Bfile.

Syntax

void close();

closeStream()

Closes the stream obtained from the Bfile.

Syntax

void closeStream(
   Stream *stream); 

stream

fileExists()

Tests whether the BFILE exists. If the BFILE exists, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool fileExists() const;

getDirAlias()

Returns a string containing the directory object associated with the BFILE.

Syntax

string getDirAlias() const;

getFileName()

Returns a string containing the file name associated with the BFILE.

Syntax

string getFileName() const;

getStream()

Returns a Stream object read from the BFILE. If a stream is already open, it is disallowed to open another stream on the Bfile object. The stream must be closed before performing any Bfile object operations.

Syntax

Stream* getStream(
   unsigned int offset = 1,
   unsigned int amount = 0);

offset

amount

getUStringDirAlias()

Returns a UString containing the directory object associated with the BFILE.

Syntax

UString getUStringDirAlias() const;

getUStringFileName()

Returns a UString containing the file name associated with the BFILE.

Syntax

UString getUStringFileName() const;

isInitialized()

Tests whether the Bfile object has been initialized. If the Bfile object has been initialized, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool isInitialized() const;

isNull()

Tests whether the Bfile object is atomically NULL. If the Bfile object is atomically NULL, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool isNull() const;

isOpen()

Tests whether the BFILE is open. The BFILE is considered to be open only if it was opened by a call on this Bfile object. (A different Bfile object could have opened this file as more than one open can be performed on the same file by associating the file with different Bfile objects). If the BFILE is open, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool isOpen() const;

length()

Returns the number of bytes (inclusive of the end of file marker) in the BFILE.

Syntax

unsigned int length() const;

open()

Opens an existing BFILE for read-only access. This function is meaningful the first time it is called for a Bfile object.

Syntax

void open();

operator=()

Assigns a Bfile object to the current Bfile object. The source Bfile object is assigned to this Bfile object only when this Bfile object gets stored in the database.

Syntax

Bfile& operator=(
   const Bfile &srcBfile);

srcBfile

operator==()

Compares two Bfile objects for equality. The Bfile objects are equal if they both refer to the same BFILE. If the Bfile objects are NULL, then FALSE is returned. If the Bfile objects are equal, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool operator==(
   const Bfile &srcBfile) const;

srcBfile

operator!=()

Compares two Bfile objects for inequality. The Bfile objects are equal if they both refer to the same BFILE. If the Bfile objects are not equal, then TRUE is returned; otherwise, FALSE is returned.

Syntax

bool operator!=(
   const Bfile &srcBfile) const;

srcBfile

read()

Reads a part or all of the BFILE into the buffer specified, and returns the number of bytes read.

Syntax

unsigned int read(
   unsigned int amt,
   unsigned char *buffer,
   unsigned int bufsize,
   unsigned int offset = 1) const;

amt

buffer

buffsize

offset

setName()

Sets the directory object and file name of the BFILE.

void setName(
   const string &dirAlias,
   const string &fileName);

void setName(
   const UString &dirAlias,
   const UString &fileName);

dirAlias

fileName

setNull()

Sets the Bfile object to atomically NULL.

Syntax

void setNull();