For many reasons users of Sunbelt PL/B may need to code some of their applications in languages other than PL/B. Unfortunately the only easy way to share data with a program written in another language was via a flat file (non indexed or aamdexed). The purpose of SUNACCESSTM is to provide access to ISAM & AAM file support capability to other languages.
If you have existing applications written in other languages, then you can extend the capabilities of those applications to support your existing database of Sunbelt ISAM and AAM files.
If you have applications that are primarily scientific or process control (more appropriate to C) but have need for database support, then you will find SUNACCESSTM attractive.
If you need to share data between PL/B applications and applications coded in other languages, then you need SUNACCESSTM. For example, process control data might have been collected in C, but can be more efficiently processed by PL/B. Or maybe all of the old business applications are written in COBOL and a bridge is needed to the new applications written in PL/B.
ISAM Access Method
- Indexed sequential access method (ISAM) files use a `key file' (ISI file) to determine which logical record in the physical text file is associated with the `key data' supplied. The ISI file acts as the control file for the processing of logical records within the physical text file. The `key data' is usually built from actual data within the logical record to be processed. However, the `key data' does not have to come from the logical record for ISAM processing.
Capabilities of the following PL/B instructions are supported for ISAM files: PREP, OPEN, CLOSE, READ, READKEY, READKS, READKP, WRITE, UPDATE, DELETE, DELETED, DELETEDK, DELETEK, INSERT, ISIINFO
Associate Access Method
- Associative access method (AAM) files allow the user to process logical records based on `collective key' information. Similar to ISAM, this method uses a control file (AAM file) to determine which logical record is to be processed based upon the key information specified. Unlike ISAM, AAM does not require a complete or specific key. However, the key information must have been extracted from data written within the logical record.
Capabilities of the following PL/B instructions are supported for AAM files: PREP, OPEN, CLOSE, READ, READKG, READKGP, READLAST, WRITE, UPDATE, DELETE, DELETEKEY, INSERT
Direct Access Method
- Direct access method (TXT) files allow the user to process a file either sequentially forwards or backwards or randomly. This method uses a control file (TXT file) to read the logical records.
Capabilities of the following PL/B instructions are supported for TXT files: PREP, OPEN, CLOSE, READ, WRITE, UPDATE, DELETE, DELETELAST, WriteEndOfFile
File Control Routines
- The file control routines are routines that can be used across all file access types. They control flushing of buffers and locking of files for multi-user access. Also included in the 9.0 release will be TRANSACTION support.
These routines include: FilePI, FilePIEnd, FLUSH, GetFilePosit, PositEndOfFile, RepositFile, TRANSACTION
File Manipulation Routines
- In addition several additional routines are provided to support creating indices, renaming file, determining file position, etc. They include:
- ERASE - delete a file.
- RENAME - change a file name.
- SORT - sort a file into another file.
- INDEX - create an ISAM file from a data file.
- AAMDEX - create an AAM file from a data file.