Use Exclamation Mark (!) Notation for Precise Referencing

ID: Q131265

3.00 WINDOWS kbprg

The information in this article applies to:

Microsoft Visual FoxPro for Windows, version 3.0

SUMMARY

Use the exclamation mark (!) notation to reference tables in databases (.DBC files). Use it to reference tables that have the same names but that exist in different databases, and use it to make code more readable. Its main purpose is to guarantee the opening of a specific table.

MORE INFORMATION

Here is the syntax:

   USE <cDatabase_name>!<cTable_name>

NOTE: Do not put spaces on either side of the exclamation mark.

Step-by-Step Example

1. Create the following directory structure:

   C:\MAIN
   C:\MAIN\ONE
   C:\MAIN\TWO

   This can be done Visual FoxPro by issuing these commands:

   CD C:\ 
   MD MAIN
   CD C:\MAIN
   MD ONE
   MD TWO

2. Issue the following commands in the Command Window:

   CD C:\MAIN\ONE
   CREATE TABLE tb_mytbl (fld1 c(10))
   CD C:\MAIN\TWO
   CREATE TABLE tb_mytbl (fld1 c(10))
   USE
   CD C:\MAIN
   CREATE DATABASE db_one
   ADD TABLE C:\MAIN\ONE\tb_mytbl
   CREATE DATABASE db_two
   ADD TABLE C:\MAIN\ONE\tb_mytbl
   SET DATABASE TO db_one

   These commands set up a scenario where a database named db_one contains
   a table named tb_mytbl, which is located in the C:\MAIN\ONE directory.
   Another database named db_two contains a different table named tb_mytbl,
   which is located in the C:\MAIN\TWO directory.

   The issue is to open the tb_mytbl table in the db_two database. The
   current database is db_one, so you can't use this command:

      USE tb_mytbl

   It would open the table in db_one located in C:\MAIN\ONE.

3. Open the tb_mytbl table in the db_two database by using this command:

   USE db_two!tb_mytbl

The exclamation mark (!) notation works in the same manner for long table names, and it makes code more readable. The notation makes it clear exactly which database holds the table of interest. It is especially useful in SQL-SELECT statements.

Additional reference words: 3.00 VFoxWin !-symbol bang symbol KBCategory: kbprg KBSubcategory: FxprgTable

Keywords          : FxprgTable 
Version           : 3.00
Platform          : WINDOWS