ASP rs.open SQL, Conn, what does 3, 1 stand for in 3,1?

RecordSet Medium open The complete grammar is  

Copy code The code is as follows :

SecordSet.Open Source,ActiveConnection,CursorType,LockType,Options  

for example ： rs.open sql,conn,1,3 

CursorType yes  
adOpenForwardOnly 0  Default cursor type ,  To open the forward cursor ,  You can only move forward in the recordset . 
adOpenKeyset 1  Open the cursor of keyset type ,  You can move forward or backward in the recordset .  If other users modify or delete a record ,  The recordset will reflect this change .  however ,  If another user adds a new record ,  New records will not appear in the recordset . 
AdOpenDynamic 2  Open dynamic cursor ,  You can move forward or backward in the recordset .  Any changes in records caused by other records will be reflected in the record set . 
adOpenStatic 3  Open the static cursor ,  You can move forward or backward in the recordset .  however ,  Static cursors will not reflect changes in records caused by other users . 

LockType yes  
adLockReadOnly 1  Read-only lock ,  Specify that the records in the recordset cannot be modified . 
adLockPrssimistic 2  Protective locking ,  When editing a record ,  Lock it now . 
adLockOptimistic 3  Open lock ,  Specifies that only the calling recordset  Update()  Method to lock the record . 
adLockBatchOptimistic 4  Open batch locking ,  Specified records can only be updated in batches . 

The two most commonly used methods : 
rs.open sql,conn,1,1 ' When reading display data , read-only  
rs.open sql,conn,1,3 ' When updating or inserting data , Reading and writing  

The following is the supplement of other netizens

recordset.Open Source,ActiveConnection,CursorType,LockType,Options

It can be written. ：
rs.open SQL sentence ,conn object ,3（ cursor type ）,2（ Locking method ）

Source
Recordset Objects can pass through Source Property to connect Command object .Source The parameter can be a Command Object name 、 a section SQL command 、 A specified data table name or a Stored Procedure. If you omit this parameter , The system uses Recordset Object's Source attribute .

ActiveConnection
Recordset Objects can pass through ActiveConnection Property to connect Connection object . there ActiveConnection It could be a Connection Object or a string containing database Connection information （ConnectionString） String parameter of .

CursorType
Recordset object Open Methodical CursorType The parameter indicates what cursor type the data will be started with , Include adOpenForwardOnly、adOpenKeyset、adOpenDynamic And adOpenStatic, It is described as follows ：

constant	Constant value	explain
adOpenForwardOnly	0 The default value	Start a cursor that can only move forward （Forward Only）
adOpenKeyset	1	Start a Keyset Cursor of type
adOpenDynamic	2	Start a Dynamic Cursor of type
adOpenStatic	3	Start a Static Cursor of type

The above cursor types will directly affect Recordset All properties and methods of the object , The following list shows the differences between them .

Recordset attribute	adOpenForwardOnly	adOpenKeyset	adOpenDynamic	adOpenStatic
AbsolutePage	I won't support it	I won't support it	read-write	read-write
AbsolutePosition	I won't support it	I won't support it	read-write	read-write
ActiveConnection	read-write	read-write	read-write	read-write
BOF	read-only	read-only	read-only	read-only
Bookmark	I won't support it	I won't support it	read-write	read-write
CacheSize	read-write	read-write	read-write	read-write
CursorLocation	read-write	read-write	read-write	read-write
CursorType	read-write	read-write	read-write	read-write
EditMode	read-only	read-only	read-only	read-only
EOF	read-only	read-only	read-only	read-only
Filter	read-write	read-write	read-write	read-write
LockType	read-write	read-write	read-write	read-write
MarshalOptions	read-write	read-write	read-write	read-write
MaxRecords	read-write	read-write	read-write	read-write
PageCount	I won't support it	I won't support it	read-only	read-only
PageSize	read-write	read-write	read-write	read-write
RecordCount	I won't support it	I won't support it	read-only	read-only
Source	read-write	read-write	read-write	read-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	I won't support it	I won't support it	I won't support it	I won't support it
Close	Support	Support	Support	Support
Delete	Support	Support	Support	Support
GetRows	Support	Support	Support	Support
Move	I won't support it	Support	Support	Support
MoveFirst	Support	Support	Support	Support
MoveLast	I won't support it	Support	Support	Support
MoveNext	Support	Support	Support	Support
MovePrevious	I won't support it	Support	Support	Support
NextRecordset	Support	Support	Support	Support
Open	Support	Support	Support	Support
Requery	Support	Support	Support	Support
Resync	I won't support it	I won't support it	Support	Support
Supports	Support	Support	Support	Support
Update	Support	Support	Support	Support
UpdateBatch	Support	Support	Support	Support

among NextRecordset The method does not apply to Microsoft Access database .

LockType
Recordset object Open Methodical LockType The parameter represents the... To be used Lock type , If you ignore this parameter , Then the system will Recordset Object's LockType Property is the default .LockType Parameters include adLockReadOnly、adLockPrssimistic、adLockOptimistic And adLockBatchOptimistic etc. , It is described as follows ：

constant	Constant value	explain
adLockReadOnly	1 The default value	Recordset Object starts as read-only , Unable to run AddNew、Update And Delete Other methods
adLockPrssimistic	2	When the data source is being updated , The system will temporarily lock the actions of other users , To maintain data consistency
adLockOptimistic	3	When the data source is being updated , The system does not lock the actions of other users , Other users can add data 、 Delete 、 Change the operation
adLockBatchOptimistic	4	When the data source is being updated , Other users must CursorLocation Attribute to adUdeClientBatch To add to the data 、 Delete 、 Change the operation

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