OCI Get Object Status Functions

This section describes the OCI get object status functions.

Table 17-8 Get Object Status functions

Function/Page	Purpose
OCIObjectExists()	Get the existent status of an instance
OCIObjectGetProperty()	Get the status of a particular object property
OCIObjectIsDirty()	Get the dirtied status of an instance
OCIObjectIsLocked()	Get the locked status of an instance

OCIObjectExists()

Purpose

Returns the existence meta-attribute of a standalone instance.

Syntax

sword OCIObjectExists ( OCIEnv         *env,
                        OCIError       *err,
                        dvoid          *ins,
                        boolean        *exist );

Parameters

env (IN/OUT)

The OCI environment handle initialized in object mode. See the description of OCIEnvCreate() and OCIInitialize() for more information.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err and this function returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

ins (IN)

Pointer to an instance. If it is an object, it must be pinned.

exist (OUT)

Return value for the existence status.

Comments

This function returns the existence of an instance. If the instance is a value, this function always returns TRUE. The instance must be a standalone persistent or transient object.

See Also:

For more information about object meta-attributes, see "Object Meta-Attributes".

Related Functions

OCIObjectPin()

OCIObjectGetProperty()

Purpose

Retrieve a given property of an object.

Syntax

sword OCIObjectGetProperty ( OCIEnv              *envh, 
                             OCIError            *errh, 
                             CONST dvoid         *obj, 
                             OCIObjectPropId     propertyId,
                             dvoid               *property, 
                             ub4                 *size );

Parameters

env (IN/OUT)

The OCI environment handle initialized in object mode. See the description of OCIEnvCreate() and OCIInitialize() for more information.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err and this function returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

obj (IN)

The object whose property is returned.

propertyId (IN)

The identifier which identifies the desired property.

property (OUT)

The buffer into which the desired property is copied.

size (IN/OUT)

On input, this parameter specifies the size of the property buffer passed by caller.

On output it contains the size in bytes of the property returned. This parameter is required for string-type properties only, such as OCI_OBJECTPROP_SCHEMA, OCI_OBJECTPROP_TABLE). For non-string properties this parameter is ignored since the size is fixed.

Comments

This function returns the specified property of the object. The desired property is identified by propertyId. The property value is copied into property and for string typed properties the string size is returned by size.

Objects are classified as persistent, transient and value depending upon the lifetime and referenceability of the object. Some of the properties are applicable only to persistent objects and some others only apply to persistent and transient objects. An error is returned if the user tries to get a property which in not applicable to the given object. To avoid such an error, the user should first check whether the object is persistent or transient or value (OCI_OBJECTPROP_LIFETIME property) and then appropriately query for other properties.

The different property ids and the corresponding type of property argument are given next.

OCI_OBJECTPROP_LIFETIME

This identifies whether the given object is a persistent object or a transient object or a value instance. The property argument must be a pointer to a variable of type OCIObjectLifetime. Possible values include:

OCI_OBJECT_PERSISTENT
OCI_OBJECT_TRANSIENT
OCI_OBJECT_VALUE

OCI_OBJECTPROP_SCHEMA

This returns the schema name of the table in which the object exists. An error is returned if the given object points to a transient instance or a value. If the input buffer is not big enough to hold the schema name an error is returned, the error message will communicate the required size. Upon success, the size of the returned schema name in bytes is returned by size. The property argument must be an array of type text and size should be set to size of array in bytes by the caller.

OCI_OBJECTPROP_TABLE

This returns the table name in which the object exists. An error is returned if the given object points to a transient instance or a value. If the input buffer is not big enough to hold the table name an error is returned, the error message will communicate the required size. Upon success, the size of the returned table name in bytes is returned by size. The property argument must be an array of type text and size should be set to size of array in bytes by the caller.

OCI_OBJECTPROP_PIN_DURATION

This returns the pin duration of the object. An error is returned if the given object points to a value instance. The property argument must be a pointer to a variable of type OCIDuration. Valid values include

OCI_DURATION_SESSION
OCI_DURATION_TRANS

See Also:
For more information about durations, see "Object Duration".

OCI_OBJECTPROP_ALLOC_DURATION

This returns the allocation duration of the object. The property argument must be a pointer to a variable of type OCIDuration. Valid values include:

OCI_DURATION_SESSION
OCI_DURATION_TRANS

For more information about durations, see "Object Duration".

OCI_OBJECTPROP_LOCK

This returns the lock status of the object. The possible lock statuses are enumerated by OCILockOpt. An error is returned if the given object points to a transient or value instance. The property argument must be a pointer to a variable of type OCILockOpt. Note, the lock status of an object can also be retrieved by calling OCIObjectIsLocked(). Valid values include:

OCI_LOCK_NONE - for no lock
OCI_LOCK_X - for an exclusive lock
OCI_LOCK_X_NOWAIT - for an exclusive lock with the NOWAIT option.

See Also:
For information about the NOWAIT option, see "Locking with the NOWAIT Option".

OCI_OBJECTPROP_MARKSTATUS

This returns the dirty status and indicates whether the object is a new object, updated object or deleted object. An error is returned if the given object points to a transient or value instance. The property argument must be of type OCIObjectMarkStatus. Valid values include:

OCI_OBJECT_NEW
OCI_OBJECT_DELETED
OCI_OBJECT_UPDATED

The following macros are available to test the object mark status:

OCI_OBJECT_IS_UPDATED (flag)
OCI_OBJECT_IS_DELETED (flag)
OCI_OBJECT_IS_NEW (flag)
OCI_OBJECT_IS_DIRTY (flag)

OCI_OBJECTPROP_VIEW

This identifies whether the specified object is a view object or not. If the property value returned is TRUE, it indicates the object is a view otherwise it is not. An error is returned if the given object points to a transient or value instance. The property argument must be of type boolean.

Related Functions

OCIObjectLock(), OCIObjectMarkDelete(), OCIObjectMarkUpdate(), OCIObjectPin(), OCIObjectPin()

OCIObjectIsDirty()

Purpose

Checks to see if an object is marked as dirty.

Syntax

sword OCIObjectIsDirty ( OCIEnv       *env,
                         OCIError     *err, 
                         dvoid        *ins,
                         boolean      *dirty );

Parameters

env (IN/OUT)

The OCI environment handle initialized in object mode. See the description of OCIEnvCreate() and OCIInitialize() for more information.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err and this function returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

ins (IN)

Pointer to an instance.

dirty (OUT)

Return value for the dirty status.

Comments

The instance passed to this function must be standalone. If the instance is an object, the instance must be pinned.

This function returns the dirty status of an instance. If the instance is a value, this function always returns FALSE for the dirty status.

Related Functions

OCIObjectMarkUpdate(), OCIObjectGetProperty()

OCIObjectIsLocked()

Purpose

Get lock status of an object.

Syntax

sword OCIObjectIsLocked ( OCIEnv       *env, 
                          OCIError     *err, 
                          dvoid        *ins,
                          boolean      *lock );

Parameters

env (IN/OUT)

The OCI environment handle initialized in object mode. See the description of OCIEnvCreate() and OCIInitialize() for more information.

err (IN/OUT)

The OCI error handle. If there is an error, it is recorded in err and this function returns OCI_ERROR. Obtain diagnostic information by calling OCIErrorGet().

ins (IN)

Pointer to an instance. The instance must be standalone, and if it is an object it must be pinned.

lock (OUT)

Return value for the lock status.

Comments

This function returns the lock status of an instance. If the instance is a value, this function always returns FALSE.

Related Functions

OCIObjectLock(), OCIObjectGetProperty()