DBASE IV version 2.0

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dBASE IV v2.0 product description

 

TOP 10 NEW ITEMS IN DBASE IV 2.0
  1. Significantly faster performance compared to v1.5.
  2. Faster and easier installation.
  3. New Virtual Memory Manager.
  4. New filter optimization technology to process filter expressions and searches.
  5. Foreign language table identification and support.
  6. Improved/New Commands and Functions.
  7. Increased array sizes.
  8. Enhanced file sharing capabilities on multi- tasking operating systems.
  9. 25, 43 and 50 line VGA display mode support.

HARDWARE/SOFTWARE REQUIREMENTS

System Requirements -

An Intel 286 - (or higher) based PC
DOS 3.3 or later, 100% - compatible versions
Minimum 640k base, 1 Mb extended RAM (2 MB extended RAM recommended); supports up to 16 Mb extended RAM
Minimum 3.5 Mb of hard disk space
Monochrome, CGA, EGA, or VGA monitor
Optional: Microsoft Windows 3.0 or later, or IBM OS/2 2.01 or later

Networks supported -

Novell NetWare v2.2 and v3.11
3Com 3+ Share v1.60 and 3Com 3+ Open v2.0
LANtastic v4.01
Banyan VINES v5.0
MS LAN Manager v2.1
IBM LAN Server v3.0
AT&T StartGROUP v3.6; - 100% compatibles to the above

Optional Equipment -

PostScript Printers, Hewlett-Packard laser printers and dot-matrix printers
Math coprocessors, Intel 80287, 80387, and 100% compatible
Pointing device: mouse

* NEW COMMANDS AND FUNCTIONS

MROW() returns the row position of the mouse pointer on the screen.

MCOL() returns the column position of the mouse pointer on the screen.

ISMOUSE() returns a logical true if a mouse driver is loaded, otherwise it returns false.

KEYMATCH() indicates whether or not a specified expression is found in the index keys of a specified index.

RAT() is a variant of the AT() function. It works the same way except it searches from the right of the source string instead of the left.

FLDLIST() returns the fields and calculated field expressions of a SET FIELDS TO list.

BARCOUNT() returns the number of bars in the active or specified popup.

BARPROMPT() returns the text that appears in a given bar of the active or specified popup.

PADPROMPT() returns the text that appears in a given pad of the active or specified bar menu.

ON BAR executes a specific command when users highlight a specific bar in a popup.

ON MENU executes a specific command when any pad of the specified menu is highlighted.

ON POPUP executes a specific command when any bar of the specified popup is highlighted.

ON SELECTION BAR executes a specific command after users highlight and then activate a specified bar in a popup.

ON SELECTION MENU executes a specific command when one of the menu pads is activated.

ON EXIT BAR executes a specific command when the users move the highlight away from a particular bar in a popup.

ON EXIT MENU executes a specific command when the users move the highlight away from specified pads in a menu.

ON EXIT PAD executes a specific command when the users move the highlight away from a particular pad in a menu.

ON EXIT POPUP executes a specific command when the users move the highlight away from a specified bars in a popup.

ON MOUSE detects when the user clicks the left mouse button and executes a command when the button is released.

* NEW SET COMMANDS

SET MOUSE ON/OFF enables or disables the mouse cursor.

SET LDCHECK ON/OFF enables or disables checking for the active language driver ID (LDID).

SET LOCALSHARE ON/OFF enables or disables checking to see if SHARE.EXE has been loaded.

SET IBLOCK TO lets the users specify the size of the indexing block size that dBASE IV uses when it creates new .MDX files.

SET MBLOCK TO lets users specify the size of the memo block size that dBASE IV uses when making new .DBT (memo field) files.

* ENVIRONMENT VARIABLES

DOS16M limits the amount (to reserve memory for other applications), of the available memory, so that, for example, under Windows 3.1 dBASE IV 2.0 does not take up as much available memory as possible.

DBASEIV_BUFF setting allocates memory to the buffer manager in the most optimal way possible.

DPMI_MEMORY_LIMIT needs to be set to a value equal to or greater than 4M when running dBASE IV version 2.0 under OS/2 (in a DOS session).

* ENHANCED COMMANDS AND FUNCTIONS

MEMORY() function lets you enter eight different parameters that gives different type of information about your system's memory.

DECLARE now lets you declare an array with as many elements as your system's virtual memory will support, as long as one dimension does not have more than 64K of elements. (The previous version of dBASE allowed a total of 1170 elements).

SET BLOCKSIZE TO now extends the maximum block size limit that can be specified from 32 to 63.

SET DISPLAY TO now supports 25,43 and 50 line VGA modes.

ON ERROR now provides programmers with more control over error trapping. The following Errors can be trapped in dBASE IV 2.0 ERROR No. Message.

56 Disk full when writing file: <filename>
210 Production .MDX file not found: <mdxname>
289 Production .MDX file damaged.
526 Index expression needs missing memory variable: <mvarname>
527 Memo file not found.

AT() function now takes an optional third argument, which is the Nth occurrence of a matching string in a given string.

TIME() function now takes an optional argument, which will return the hundredths of seconds in the time string.

LASTKEY() now returns a value for a mouse click. If the last user action during a keyboard wait state is a mouse click, LASTKEY() returns -100.

APPEND FROM adds a NOVERIFY clause when APPENDing records FROM SDF files, which turns off error- checking and data validation during APPEND.

DEBUGger adds the following keys.

Ctrl-T Toggles a breakpoint on the selected line.
Ctrl-L Continue from selected line.
PgUp/PgDn Moves up/down one page in the source code.
Ctrl-PgUp Moves to the top of the source code.
Ctrl-PgDn Moves to the bottom of the source code.

ON PAD command now allows you to carry out a specific command when users highlight a specific pad in a menu.

* OTHER FEATURES/ISSUES

APPEND FROM 
In previous versions of dBASE, when you used the SDF or DELIMITED clauses with the APPEND FROM command, the form feed character was appended to the database. Now, the form feed is not appended to the database if it is preceded by a carriage return.

REPLACE 
If you are running dBASE in a multiuser environment, and you use the REPLACE ALL command to replace an indexed field, while keeping the index tag that acts on that particular field active, you are now required to have exclusive use of the database. This ensures that all records are replaced properly.

USE AGAIN 
If you use a database in more than one work area, any changes made to the file in one work area are reflected in the other work areas in which the same file could be open. Previously, if you used the same database in more than one work area, updates to the database in one work area were not reflected in the others.

VMM SETTINGS 
In the dBASE directory there will be a file called DBASE.VMC that contains all the configurations for the Virtual Memory Manager.

LOCALSHARE 
dBASE, now provides file sharing and locking under OS/2 and Windows., and could run in multiple sessions. You can now load dBASE IV 2.0 in 9 different sessions, and use the same files safely in more than one session. Also the dBASE file can be shared with other applications, such as Paradox for Windows.

To support file-sharing on a local system, dBASE provides you with the option of protecting your dBASE files from multi-tasking collisions with a new CONFIG.DB setting called LOCALSHARE. If you intend to share files on a local system, load SHARE.EXE from DOS prior to loading Windows.

DIAGNOSTICS 
When dBASE terminates abnormally with an unrecoverable error, it automatically creates a file, DBASE.ERR for diagnostic purposes. This file contains information about the dBASE version, time at which the error occurred, error code, register status, and so on.

 

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