Tutorial: Creating A Multi-User Network Application Tutorial: Creating A FoxPro Multi-User Application Dr. Hicks Computer Science Department Trinity University Background Information & Other Tutorials For purposes of this tutorial, we shall start with the single user application created in the following tutorial.
1] Our RestaruantApp still resides in folder. (See Below!) 2] The Project may be seen below: Open The Database & Tables Exclusively 1] By default the Use command opens the database in exclusive mode.
A second user may not open either the database or the table. Note the exclusive on the status bar. Madame bamboo 1991. Open Database Rest Use Data Rest Order Name Open The Database & Tables Shared 1] Let us now attempt to open database Rest and table Rest simultaneously on two foxpro appplications. These applications my be on two different computers; they may also be on the same computer as illustrated below. Open Database Rest Shared Use Data Rest Shared Order Name 2] No longer does it say exclusive at the bottom of the status bar.
Membuat Program Minimarket Dengan Microsoft Visual Foxpro 9.0 adalah sebuah buku panduan membuat program yang sederhana dengan menggunakan Microsoft Visual Foxpro 9.0,buku ini di desaign. Tutorial Dasar Belajar Pembuatan Program Aplikasi. Membuat Program Penjualan, data entri Dengan Microsoft Visual Foxpro 9.0 adalah sebuah Program untuk membuat program yang sederhana dengan menggunakan Microsoft Visual Foxpro 9.0 yang mengulas tentang Program Aplikasi Penjualan, data entri yang didesaign dengan 3 hak akses untuk Teller, untuk Manager perusahaan,dan Admin.
The active record on both applications is record 1 of 54. Any function or form that enables the user to alter a record automatically lock the record as soon as a change is initiated. Edit and Change are two such functions.
In the screen capture below, The top user is going to and a 2 is added to the end of the restaurant name; you can see Record Locked in the status bar as soon as the change is initiated. Once a user locks the record while making a change, it shall stay locked until the user moves to the next record.(See Below!) 3] Fortunately, locking the record does not prevent the other users from searching,running reports, running labels, examining data, or selection type queries. As you can see below, the bottom user can attempt to edit the same record and shall be successful until he/she attempts to make a change. (See Below!) 4] When the bottom user attempts to add a 2 to the end of the city Odessa, he/she gets a message Attempting To Lock. Press Esc To Cancel.
As soon as the top exits or moves on to another record, the bottom user will get a lock and be able to make his/her change. Really 'klugy' at this stage. (See Below!) 5] In the screen capture below, the top user finished editing record 1 and closed the edit window; the bottom user received a lock on record 1 and is able to make his/her change to Odessa. Cadsoft envisioneer 3.0.
(See Below!) 6] Forms only compound these problems! Two Form Modes - Edit Mode & Normal Mode 1] There are two basic modes.
• The Edit Mode shall lock the current database record and permit changes to that record. • Options within this mode shall be only Cancel & Save • The Normal Mode shall enable the user to • Options within this mode shall be all else ==> Next, Previous, Top, Bottom, Search, Print, Browse, Edit, Add, Delete, Exit, etc. 2] For educational purposes, let us add two temporary buttons to our Rest form. (See Below!) • The valid event for the Edit Mode button should be Do SetEditMode • The valid event for the Normal Mode button should be Do SetNormalMode Normal Mode Should Allow No Option To Change The Record Fields - Scatter Memvar Memo 1] It is customary to work with a copy of the data in the edit mode; this greatly facilitates the ease of canceling the process with no damage to the original data. Some databases, such as FoxPro, have the option to easily create a set of local variables which contain a copy of the information in the current record; this function is called Scatter in the x-base languages. In other database applications, such as Access, the programmer has to manually create and assign the needed local variables. 2] As you already know, Display Memory, will display all of the local variables -- followed by all of the system variables, etc.
In the screen capture below, you can see that local variable NewName was assigned the value Dr.Thomas E. Hicks; Display memory shows this immediately before all of the system variable. (See Below!) 3] The current record is record 1 of 54. The Customer record has 9 fields; the notes field is a memo field. Scatter Memvar Memo creates 9 new local variables whose names are the same as those in the current record and whose values match those of the current record. Scatter Memvar makes a copy of all fields except memo fields. (See Below!) 3] The database field Name takes precedence over the local memory variable Name; therefore,?