What does the ASP Rs.Open sql,conn,3,1 3, 1 represent? _asp Foundation

The open complete syntax in the recordset is

Copy Code code as follows:

Secordset.open source,activeconnection,cursortype,locktype,options

For example: Rs.Open sql,conn,1,3

CursorType is
adOpenForwardOnly 0 The default cursor type, which opens forward cursors and moves forward only in the recordset.
adOpenKeyset 1 opens a keyset-type cursor that can be moved forward or backward in the recordset. If another user modifies or deletes a record, the recordset reflects the change. However, if another user adds a new record, the new record does not appear in the recordset.
adOpenDynamic 2 opens a dynamic cursor that can be moved forward or backward in the recordset. Any changes in the records resulting from other notes will be reflected in the recordset.
adOpenStatic 3 Opens a static cursor that can be moved forward or backward in the recordset. However, static cursors do not reflect record changes caused by other users.

LockType is
adLockReadOnly 1 Read-only locks, specifying that records in the recordset cannot be modified.
Adlockprssimistic 2 protected locking, which is locked immediately when editing a record.
adLockOptimistic 3 Open locks, specifying that records can be locked only when the Update () method of the recordset is invoked.
adLockBatchOptimistic 4 Open Batch locks, specifying that records can only be updated in batches.

two of the most common methods:
Rs.Open sql,conn,1,1 ' reads when displaying data, read only
Rs.Open sql,conn,1,3 ' when updating or inserting data, reading and writing

The following are the supplements of other netizens

Recordset. Open source,activeconnection,cursortype,locktype,options

Can be written as:
Rs.Open SQL statement, Conn object, 3 (cursor type), 2 (locking method)

Source
The Recordset object can connect to the command object through the Source property. The source parameter can be a command object name, a section of SQL command, a specified data table name, or a stored Procedure. If this argument is omitted, the system takes the source property of the Recordset object.

ActiveConnection
The Recordset object can connect connection objects by ActiveConnection properties. The ActiveConnection can be a connection object or a string parameter containing the database connection information (ConnectionString).

CursorType
The CursorType parameter of the Recordset object Open method indicates what cursor type will start the data, including adOpenForwardOnly, adOpenKeyset, adOpenDynamic, and adOpenStatic. It is described as follows:

Constant	Constant value	Description
adOpenForwardOnly	0 default values	Start a cursor that can only be moved forward (Forward only)
adOpenKeyset	1	Launches a keyset type of cursor
adOpenDynamic	2	Start a cursor of the dynamic type
adOpenStatic	3	Start a static type of cursor

These cursor types will directly affect all properties and methods of the Recordset object, and the following list illustrates the differences between them.

Recordset Properties	adOpenForwardOnly	adOpenKeyset	adOpenDynamic	adOpenStatic
AbsolutePage	does not support	does not support	can read and write	can read and write
AbsolutePosition	does not support	does not support	can read and write	can read and write
ActiveConnection	can read and write	can read and write	can read and write	can read and write
BOF	Read-only	Read-only	Read-only	Read-only
Bookmark	does not support	does not support	can read and write	can read and write
CacheSize	can read and write	can read and write	can read and write	can read and write
CursorLocation	can read and write	can read and write	can read and write	can read and write
CursorType	can read and write	can read and write	can read and write	can read and write
EditMode	Read-only	Read-only	Read-only	Read-only
Eof	Read-only	Read-only	Read-only	Read-only
Filter	can read and write	can read and write	can read and write	can read and write
LockType	can read and write	can read and write	can read and write	can read and write
MarshalOptions	can read and write	can read and write	can read and write	can read and write
MaxRecords	can read and write	can read and write	can read and write	can read and write
PageCount	does not support	does not support	Read-only	Read-only
PageSize	can read and write	can read and write	can read and write	can read and write
RecordCount	does not support	does not support	Read-only	Read-only
Source	can read and write	can read and write	can read and write	can read and write
State	Read-only	Read-only	Read-only	Read-only
Status	Read-only	Read-only	Read-only	Read-only
AddNew	Support	Support	Support	Support
CancelBatch	Support	Support	Support	Support
CancelUpdate	Support	Support	Support	Support
Clone	does not support	does not support	does not support	does not support
Close	Support	Support	Support	Support
Delete	Support	Support	Support	Support
GetRows	Support	Support	Support	Support
Move	does not support	Support	Support	Support
MoveFirst	Support	Support	Support	Support
MoveLast	does not support	Support	Support	Support
MoveNext	Support	Support	Support	Support
MovePrevious	does not support	Support	Support	Support
NextRecordset	Support	Support	Support	Support
Open	Support	Support	Support	Support
Requery	Support	Support	Support	Support
Resync	does not support	does not support	Support	Support
Supports	Support	Support	Support	Support
Update	Support	Support	Support	Support
UpdateBatch	Support	Support	Support	Support

Where the NextRecordset method does not apply to Microsoft Access databases.

LockType
The LockType parameter of the Recordset object's Open method represents the lock type to take, and if this argument is omitted, then the system takes the LockType property of the Recordset object as the preset value. The LockType parameters include adLockReadOnly, adlockprssimistic, adLockOptimistic, and adLockBatchOptimistic, as described below:

Constant	Constant value	Description
adLockReadOnly	1 Default values	The Recordset object starts as read-only and cannot run AddNew, Update, and Delete methods
Adlockprssimistic	2	When the data source is being updated, the system temporarily locks the actions of other users to maintain data consistency
adLockOptimistic	3	When the data source is being updated, the system does not lock other users ' actions, other users can add, delete, and change the operation of the data
adLockBatchOptimistic	4	When the data source is being updated, other users must change the CursorLocation property to Adudeclientbatch to add, delete, and modify the data

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