Oracle® C++ Call Interface Programmer's Guide, 11g Release 2 (11.2) Part Number E10764-02 |
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OCCI provides object navigational calls that enable applications to perform any of the following on objects:
Creating, accessing, locking, deleting, copying, and flushing objects
Getting references to the objects
This class enables the type definer to specify when a class can have persistent or transient instances. Instances of classes derived from PObject
are either persistent or transient. For example, class A
that is persistent-capable inherits from the PObject
class:
class A : PObject { ... }
The only methods valid on a NULL
PObject
are setName(), isNull(), and operator=().
Some methods, such as lock(), apply only for persistent instances, not for transient instances.
Table 13-31 Enumerated Values Used by PObject Class
Attribute | Options |
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LockOption |
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UnpinOption |
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Table 13-32 Summary of PObject Methods
Method | Summary |
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Flushes a modified persistent object to the database server. |
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Returns the connection from which the |
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Returns a reference to a given persistent object. |
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Returns the Oracle database typename for this class. |
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Tests whether the persistent object is locked. |
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Tests whether the object is |
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Lock a persistent object on the database server. The default mode is to wait for the lock if not available. |
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Marks a persistent object as deleted. |
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Marks a persistent object as modified or dirty. |
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Assigns one |
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Remove the persistent object from the application cache only. |
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Creates a new persistent / transient instance. |
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Pins an object. |
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Sets the object value to |
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Unmarks an object as dirty. |
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Unpins an object. In the default mode, the pin count of the object is decremented by one. |
PObject
class constructor.
Syntax | Description |
---|---|
PObject(); |
Creates a NULL PObject. |
PObject( const PObject &obj); |
Creates a copy of PObject. |
Parameter | Description |
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obj |
The source object. |
This method flushes a modified persistent object to the database server.
void flush();
Returns the connection from which the persistent object was instantiated.
const Connection *getConnection() const;
This method returns a reference to the persistent object.
RefAny getRef() const;
Returns the Oracle database typename for this class.
string getSQLTypeName() const;
This method test whether the persistent object is locked. If the persistent object is locked, then TRUE
is returned; otherwise, FALSE
is returned.
bool isLocked() const;
This method tests whether the persistent object is NULL
. If the persistent object is NULL
, then TRUE
is returned; otherwise, FALSE
is returned.
bool isNull() const;
Locks a persistent object on the database server.
void lock( PObject::LockOption lock_option);
Parameter | Description |
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lock_option |
Locking options; see Table 13-31. |
This method marks a persistent object as deleted.
void markDelete();
This method marks a persistent object as modified or dirty.
void mark_Modified();
This method assigns the value of a persistent object this PObject
object. The nature (transient or persistent) of the object is maintained. NULL
information is copied from the source instance.
PObject& operator=( const PObject& obj);
Parameter | Description |
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obj |
The object from which the assigned value is obtained. |
Deletes a persistent or transient object. The delete operator on a persistent object removes the object from the application cache only. To delete the object from the database server, invoke the markDelete() method.
void operator delete( void *obj, size_t size);
Parameter | Description |
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obj |
The pointer to object to be deleted |
size |
(Optional) Size is implicitly obtained from the object |
This method creates a new object. A persistent object is created if the connection and table name are provided. Otherwise, a transient object is created.
Syntax | Description |
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void *operator new( size_t size); |
Creates a default new object, with a size specification only |
void *operator new( size_t size, const Connection *conn, const string& tableName, const char *typeName); |
Used for creating transient objects when client side characterset is multibyte. |
void *operator new( size_t size, const Connection *conn, const string& tableName, const string& typeName, const string& schTableName="", const string& schTypeName=""); |
Used for creating persistent objects when client side characterset is multibyte. |
void *operator new( size_t size, const Connection *conn, const UString& tableName, const UString& typeName, const UString& schTableName="", const UString& schTypeName=""); |
Used for creating persistent objects when client side characterset is unicode (UTF16). |
Parameter | Description |
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size |
size of the object |
conn |
The connection to the database in which the persistent object is to be created. |
tableName |
The name of the table in the database server. |
typeName |
The SQL type name corresponding to this C++ class. The format is <schemaname>.<typename> . |
schTableName |
The schema table name. |
schTypeName |
The schema type name. |
This method pins the object and increments the pin count by one. If the object is pinned, it is not freed by the cache even if there are no references to this object instance.
void pin();
This method sets the object value to NULL
.
void setNull();
This method unmarks a persistent object as modified or deleted.
void unmark();
This method unpins a persistent object. In the default mode, the pin count of the object is decremented by one. When this method is invoked with OCCI_PINCOUNT_RESET
, the pin count of the object is reset. If the pin count is reset, this method invalidates all the references (Ref
s) pointing to this object. The cache sets the object eligible to be freed, if necessary, reclaiming memory.
void unpin( UnpinOption mode=OCCI_PINCOUNT_DECR);
Parameter | Description |
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mode |
Specifies whether the UnpinOption mode, or the pin count, should be decremented or reset to 0 . See Table 13-31. Valid values are OCCI_PINCOUNT_RESET and OCCI_PINCOUNT_DECR . |