Kompatabilität zwischen dBASE DOS und dBASE

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Tables

All previous tables, index and memo files are compatible with the öatest versions. Conversion is not necessary..

However dBase Plus now ofer the newer "Level 7" tables. These tables offer a wide range of new features. For example default values can be defined for each field. New field types such as BLOB for storing binary data (eg: jpg, gif, and other image formats.) or autoincrement for generating a unique number in every record.

@ say / @ get

These commands are no longer supported whereby the reason lies not in dBase but rather in the underlying technology modern gui operating systems. Windows is object oriented. Every text we see on the screen is an object with properties.No longer is there a concept of lines by columns which is the way the old say/get comands were designed to work.

Printer Output

In the days of DOS print data contained a stream of data and format escape sequences. Often the formating codes between different printers even from the same manufacturer were entirely different.

Sometimes these sequences will still work. The basic "?" command still functions, and you will need to test your print output on an individual basis to see if they still work to your satisfaction.

Browse

The old browse command was extremely powerfull with masses of formatting options and a good deal of functional capabilities.

dBase Plus still recognizes the browse command and has a browse object included in its classes but the object does not have all the capabilities of the original feature.

dBase Plus relies mainly on the "Grid" object which can be datalinked to queries embedded in forms. Unfortunately you cannot datalink a "Grid" to a table or resultset which was opened using the old xdml commands (use).

xdml Commands

Most xdml commands still work as they did in DOS days.

For example:


USE clients ORDER clientnumber ALIAS client

GO TOP

DO WHILE NOT EOF()

  IF client->postcode = "8"

    ? client->clientnumber,cliemt->name,"lives in ",client->town

    REPLACE replace->state with "Bavaria"

  ENDIF

  SKIP

ENDDO

CLOSE DATA



Functions the way it did 15 years ago.


Dot Commands

In Dos you wrote commands following the famous dot.The same applies to dBase Plus except that commands are entered in the upper area of the command window.

Results are diplayed in the lower area.

This capability of testing out and using single commands interactively is one feature which makes dBBase stand out among the host of programming languages.

&Macros

Those who loved to use macros, need not change their code. We recommend though, that you always add a single dot after the macro, because the dBase Plus interpreter seems sometimes to get confused if you don't.

Functions

All the well known functions like: trim(), left(), substr().... still work as before.

Sometimes it is worth taking a look at the newer classes and methods for processing dates and Strings which provide even greater functionality.

The Navigator

The Navigator is still around. Much easier to use than in DOS.

Code

Borland defined the term "Two-Way-Tools". dBase PLUS uses this concept throughout. Everything you do with a GUI tool can be viewd in source-code mode using the new editor. Again an outstanding dBase feature.

Summary:

If your DOS application consists mainly of Dialogs (Forms/Masks) then you will probably need to change/rewrite large parts of it. Remember though that if you were to decide to use another language that the amount to learn would be far higher and you would probably have to rewrite everything.

The basics are still dBase they way it always was.


Many programs and modules which have little or no dialog functionality can be used unchanged.