Description
Creates a table access variable (a file handle).
Syntax
Open ["DICT",] expression To table_var Then | Else statements
Parameters
The Open statement has the following parameters.
| Parameter | Description |
|---|---|
| expression | Designates the native table that is to be opened. To open the dictionary, use DICT as the first part of the table name (example: "DICT.CUSTOMERS"); and to open the data portion of the table, use only the table name (example: "CUSTOMERS"). Use separate Open statements to open the DICT and data portions of each table. |
| table_var | After a successful Open operation, table_var contains information about the table. From that point on, refer to the table with table_var, not with the actual table name. |
| Then | The statement(s) following Then are executed if a table is opened successfully. |
| Else | The statement(s) following Else are executed if the table cannot be opened. The Status() function indicates the severity of the error, and the system variable @FILE_ERROR contains detail about the nature of the error. |
You must Open a table before attempting to Read or Write rows from/to that table. As long as a table has been opened once, it does not need to be opened again each time you want to Read or Write to it.
Each table must be opened with a separate Open statement. Any number of tables may be opened at any point in the program.
Tables opened with the Open command need not and cannot be closed.
See also
Index.Open subroutine, Attach_Table
Example
/* The following program demonstrates file opening and subsequent processing. */
table = "CAR_PARTS"
Open table To tablevar Then
Open "DICT", table To @DICT Else null
End Else
* error processing: cannot open table
End
Select tablevar
Done = 0
Printer On
Loop
ReadNext @ID Else done = 1
Until done
Read @RECORD From tablevar, @ID Then
report = {PART_NAME}:" ":{PART_TYPE}:" ":{PART_NO}
Print report
End
Repeat
Printer Off
