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Class postgresql.largeobject.LargeObjectManager
java.lang.Object
|
+----postgresql.largeobject.LargeObjectManager
- public class LargeObjectManager
- extends Object
This class implements the large object interface to postgresql.
It provides methods that allow client code to create, open and delete
large objects from the database. When opening an object, an instance of
postgresql.largeobject.LargeObject is returned, and its methods then allow
access to the object.
This class can only be created by postgresql.Connection
To get access to this class, use the following segment of code:
import postgresql.largeobject.*;
Connection conn;
LargeObjectManager lobj;
... code that opens a connection ...
lobj = ((postgresql.Connection)myconn).getLargeObjectAPI();
Normally, client code would use the getAsciiStream, getBinaryStream,
or getUnicodeStream methods in ResultSet, or setAsciiStream,
setBinaryStream, or setUnicodeStream methods in PreparedStatement to
access Large Objects.
However, sometimes lower level access to Large Objects are required,
that are not supported by the JDBC specification.
Refer to postgresql.largeobject.LargeObject on how to manipulate the
contents of a Large Object.
- See Also:
- LargeObject, getAsciiStream, getBinaryStream, getUnicodeStream, setAsciiStream, setBinaryStream, setUnicodeStream, getAsciiStream, getBinaryStream, getUnicodeStream, setAsciiStream, setBinaryStream, setUnicodeStream
-
READ
- This mode indicates we want to read an object
-
READWRITE
- This mode is the default.
-
WRITE
- This mode indicates we want to write to an object
-
LargeObjectManager(Connection)
- Constructs the LargeObject API.
-
create()
- This creates a large object, returning its OID.
-
create(int)
- This creates a large object, returning its OID
-
delete(int)
- This deletes a large object.
-
open(int)
- This opens an existing large object, based on its OID.
-
open(int, int)
- This opens an existing large object, based on its OID
-
unlink(int)
- This deletes a large object.
WRITE
public static final int WRITE
- This mode indicates we want to write to an object
READ
public static final int READ
- This mode indicates we want to read an object
READWRITE
public static final int READWRITE
- This mode is the default. It indicates we want read and write access to
a large object
LargeObjectManager
public LargeObjectManager(Connection conn) throws SQLException
- Constructs the LargeObject API.
Important Notice
This method should only be called by postgresql.Connection
There should only be one LargeObjectManager per Connection. The
postgresql.Connection class keeps track of the various extension API's
and it's advised you use those to gain access, and not going direct.
open
public LargeObject open(int oid) throws SQLException
- This opens an existing large object, based on its OID. This method
assumes that READ and WRITE access is required (the default).
- Parameters:
- oid - of large object
- Returns:
- LargeObject instance providing access to the object
- Throws: SQLException
- on error
open
public LargeObject open(int oid,
int mode) throws SQLException
- This opens an existing large object, based on its OID
- Parameters:
- oid - of large object
- mode - mode of open
- Returns:
- LargeObject instance providing access to the object
- Throws: SQLException
- on error
create
public int create() throws SQLException
- This creates a large object, returning its OID.
It defaults to READWRITE for the new object's attributes.
- Returns:
- oid of new object
- Throws: SQLException
- on error
create
public int create(int mode) throws SQLException
- This creates a large object, returning its OID
- Parameters:
- mode - a bitmask describing different attributes of the new object
- Returns:
- oid of new object
- Throws: SQLException
- on error
delete
public void delete(int oid) throws SQLException
- This deletes a large object.
- Parameters:
- oid - describing object to delete
- Throws: SQLException
- on error
unlink
public void unlink(int oid) throws SQLException
- This deletes a large object.
It is identical to the delete method, and is supplied as the C API uses
unlink.
- Parameters:
- oid - describing object to delete
- Throws: SQLException
- on error
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