ADO WillExecuteและ ExecuteComplete Events
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- เหตุการณ์WillExecuteสามารถเริ่มทำงานก่อนการเรียก objcomm.Execute, objconn.Execute หรือ objrs.Open
- เหตุการณ์ExecuteCompleteสามารถเริ่มทำงานได้หลังจากการเรียก objcomm.Execute, objconn.Execute, objrs.Open, objrs.Requery หรือ objrs.NextRecordset เสร็จสมบูรณ์
ไวยากรณ์
WillExecute src,cursortyp,locktyp,options,
status,objcomm,objrs,objconn
ExecuteComplete recaffected,objerror,status,
objcomm,objrs,objconn
| Parameter | Description |
|---|---|
| src | A string that contains an SQL command or a stored procedure name |
| cursortyp | Specifies the type of cursor to be used. One of the CursorTypeEnum values |
| locktyp | Specifies the type of lock to be used. One of the LockTypeEnum values |
| options | One or more of the CommandTypeEnum or ExecuteOptionEnum values |
| recaffected | The number of records affected by the execution |
| objerror | An Error object that contains the errors that occurred
Note: The EventStatusEnum value must be set to adStatusErrorsOccurred to create the Error object |
| status | An EventStatusEnum value |
| objcomm | For WillExecute: Set to the Command object that was executed or to
Nothing
For ExecuteComplete: The Command object that was executed |
| objrs | For WillExecute: Set to the Recordset object that resulted from the execution of the command or to
Nothing
For ExecuteComplete: The Recordset object that is the result of the executed command |
| objconn | The Connection object that is associated with the execution of the command |
CursorTypeEnum ค่า
ระบุชนิดของเคอร์เซอร์ที่ใช้ในอ็อบเจ็กต์ Recordset
| Constant | Value | Description |
|---|---|---|
| adOpenUnspecified | -1 | Does not specify the type of cursor. |
| adOpenForwardOnly | 0 | Default. Uses a forward-only cursor. Identical to a static cursor, except that you can only scroll forward through records. This improves performance when you need to make only one pass through a Recordset. |
| adOpenKeyset | 1 | Uses a keyset cursor. Like a dynamic cursor, except that you can't see records that other users add, although records that other users delete are inaccessible from your Recordset. Data changes by other users are still visible. |
| adOpenDynamic | 2 | Uses a dynamic cursor. Additions, changes, and deletions by other users are visible, and all types of movement through the Recordset are allowed, except for bookmarks, if the provider doesn't support them. |
| adOpenStatic | 3 | Uses a static cursor. A static copy of a set of records that you can use to find data or generate reports. Additions, changes, or deletions by other users are not visible. |
LockTypeEnum ค่า
| Constant | Value | Description |
|---|---|---|
| adLockUnspecified | -1 | Does not specify a type of lock. For clones, the clone is created with the same lock type as the original. |
| adLockReadOnly | 1 | Indicates read-only records. You cannot alter the data. |
| adLockPessimistic | 2 | Indicates pessimistic locking, record by record. The provider does what is necessary to ensure successful editing of the records, usually by locking records at the data source immediately after editing. |
| adLockOptimistic | 3 | Indicates optimistic locking, record by record. The provider uses optimistic locking, locking records only when you call the Update method. |
| adLockBatchOptimistic | 4 | Indicates optimistic batch updates. Required for batch update mode. |
CommandTypeEnum ค่า
| Constant | Value | Description |
|---|---|---|
| adCmdUnspecified | -1 | Does not specify the command type argument. |
| adCmdText | 1 | Evaluates CommandText as a textual definition of a command or stored procedure call. |
| adCmdTable | 2 | Evaluates CommandText as a table name whose columns are all returned by an internally generated SQL query. |
| adCmdStoredProc | 4 | Evaluates CommandText as a stored procedure name. |
| adCmdUnknown | 8 | Indicates that the type of command in the CommandText property is not known. |
| adCmdFile | 256 | Evaluates CommandText as the file name of a persistently stored Recordset. Used with Recordset.Open or Requery only. |
| adCmdTableDirect | 512 | Evaluates CommandText as a table name whose columns are all returned. Used with Recordset.Open or Requery only. To use the Seek method, the Recordset must be opened with adCmdTableDirect. This value cannot be combined with the ExecuteOptionEnum value adAsyncExecute. |
ค่า ExecuteOptionEnum
| Constant | Value | Description |
|---|---|---|
| adOptionUnspecified | -1 | Indicates that the command is unspecified. |
| adAsyncExecute | 16 | Indicates that the command should execute asynchronously. This value cannot be combined with the CommandTypeEnum value adCmdTableDirect. |
| adAsyncFetch | 32 | Indicates that the remaining rows after the initial quantity specified in the CacheSize property should be retrieved asynchronously. |
| adAsyncFetchNonBlocking | 64 | Indicates that the main thread never blocks while retrieving. If the requested row has not been retrieved, the current row automatically moves to the end of the file. If you open a Recordset from a Stream containing a persistently stored Recordset, adAsyncFetchNonBlocking will not have an effect; the operation will be synchronous and blocking. adAsynchFetchNonBlocking has no effect when the adCmdTableDirect option is used to open the Recordset. |
| adExecuteNoRecords | 128 | Indicates that the command text is a command or stored procedure that does not return rows (for example, a command that only inserts data). If any rows are retrieved, they are discarded and not returned. adExecuteNoRecords can only be passed as an optional parameter to the Command or Connection Execute method. |
| adExecuteStream | 256 | Indicates that the results of a command execution should be returned as a stream. adExecuteStream can only be passed as an optional parameter to the Command Execute method. |
| adExecuteRecord | 512 | Indicates that the CommandText is a command or stored procedure that returns a single row which should be returned as a Record object. |
EventStatusค่า Enum
| Constant | Value | Description |
|---|---|---|
| adStatusOK | 1 | The operation that fired the event was successful |
| adStatusErrorsOccurred | 2 | The operation that fired the event failed |
| adStatusCantDeny | 3 | Cannot cancel the pending operation |
| adStatusCancel | 4 | Cancels the operation that fired the event |
| adStatusUnwantedEvent | 5 | Prevents subsequent notifications before the event method has finished executing |
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