See Also: Get_Attribute, Set_Attribute
The access mode for the table.
Table
All Drivers
Flag of bits, temporary
Read / Write
Any iored combination of the following modes:
DF_FILEMODE_DEFAULT, DF_FILEMODE_NO_REREAD, DF_FILEMODE_NO_LOCKS, DF_FILEMODE_NO_EDITS, DF_FILEMODE_NO_DELETES, DF_FILEMODE_NO_FINDS, DF_FILEMODE_NO_CREATES
Predefined combinations of the above:
DF_FILEMODE_READONLY, DF_FILEMODE_SINGLE_USER
Access modes affect operational characteristics of a table.
Constant |
Value |
Meaning |
DF_FILEMODE_DEFAULT |
0 |
No access restrictions on the table. |
DF_FILEMODE_NO_REREAD |
1 |
Reread on the table is not allowed. |
DF_FILEMODE_NO_LOCKS |
2 |
The table will not be locked. |
DF_FILEMODE_SINGLE_USER |
3 |
Table is opened in single user mode. |
DF_FILEMODE_NO_EDITS |
8 |
Records in the table cannot be edited. |
DF_FILEMODE_NO_DELETES |
16 |
Records in the table cannot be deleted. |
DF_FILEMODE_NO_FINDS |
32 |
Records in the table cannot be found. |
DF_FILEMODE_NO_CREATES |
64 |
Records in the table cannot be created. |
DF_FILEMODE_READONLY |
91 |
Table is opened in read-only mode. |
DF_FILEMODE_READONLY combines DF_FILEMODE_NO_REREAD, DF_FILEMODE_NO_LOCKS, DF_FILEMODE_NO_EDITS, DF_FILEMODE_NO_DELETES, and DF_FILEMODE_NO_CREATES.
DF_FILEMODE_SINGLE_USER combines DF_FILEMODE_NO_REREAD and DF_FILEMODE_NO_LOCKS.
You can make your own combinations of access restrictions by using the bitwise or operator (ior) to combine individual modes. If for example you would want to place a restriction on table MyTable that no records can be created or updated you would use the following code fragment:
Set_Attribute DF_FILE_MODE Of MyTable.File_Number to ;
(DF_FILEMODE_NO_EDITS iOr DF_FILEMODE_NO_CREATES)
It is expected that the only settings an average DataFlex programmer will need are DF_FILEMODE_DEFAULT and DF_FILEMODE_READONLY. Since the DataSet and DataDictionary classes support smart file mode, setting the file mode is not needed to tune for lock performance. Setting file mode to read only for reporting can improve report speed.
Function OverallTotal Returns Number
Number nTotal
Integer iOrgMode
Get_Attribute DF_FILE_MODE of OrderHea.File_Number to iOrgMode
Set_Attribute DF_FILE_MODE of OrderHea.File_Number to DF_FILEMODE_READONLY
Clear OrderHea
Find Gt OrderHea By 1
While (Found)
Add OrderHea.Order_total to nTotal
Find GT OrderHea By 1
End
Set_Attribute DF_FILE_MODE Of OrderHea.File_Number to iOrgMode
Function_Return nTotal
End_Function
The sample function above sets the file mode of the OrderHea table temporarily to read only and then calculates to total amount of all orders.