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dos_database_driver.htm
Navigation:  ISAM File Drivers > DOS Database Driver >====== DOS Database Driver ====== Previous pageReturn to chapter overviewNext page

Database Drivers

Choosing the Right Database Driver

Common Database Driver Features

Driver Strings

DOS:Specifications

DOS:Data Types

DOS:Supported Commands and Attributes

DOS:Driver Strings

DOS:Specifications

The DOS file driver reads and writes any binary, byte-addressable files. Neither fields nor records are delimited. When reading a record, the driver reads the number of bytes defined in the file's RECORD structure, unless a length parameter is specified in the GET statement.

The DOS driver supports the length parameter for the ADD, APPEND, GET, and PUT statements; this allows for variable length records in a DOS file.

The POINTER function returns the relative byte position within the file of the beginning of the last record accessed by an ADD, APPEND, GET, or NEXT statement.

This file driver performs forward sequential processing only. No key or transaction processing functions are supported, and the PREVIOUS statement is not supported.

TipBox.jpg

Due to its limitations, the main function of this driver is as a disk editor for binary files.

Files: ClaDOSXL.LIB Windows Static Link Library
ClaDOSX.LIB Windows Export Library
ClaDOSX.DLL Windows Dynamic Link Library (32-bit)

DOS:Data Types

BYTE DECIMAL
SHORT PDECIMAL
USHORT STRING
LONG CSTRING
ULONG PSTRING
SREAL DATE
REAL TIME
BFLOAT4 GROUP
BFLOAT8

DOS:File Specifications/Maximums

File Size:            4,294,967,295

Records per File:     4,294,967,295

Record Size:          64K

Field Size:           64K

Fields per Record:    64K

Keys/Indexes per File:n/a

Key Size:             n/a

Memo fields per File: n/a

Memo Field Size:      n/a

Open Data Files:      Operating system dependent

dos_database_driver.htm.txt · Last modified: 2021/04/15 15:57 by 127.0.0.1