Sculptor databases¶
The Sculptor keyed file system is a central feature of the Sculptor program development suite. It is easy to use, and very powerful.
A keyed file contains records, which are inserted into the file and maintained by means of Sculptor commands. Each record is divided into a number of individual data items known as fields. The records and fields are of a fixed length, which is determined by the record layout of the keyed file. The record layout is specified in a data dictionary, created by the Sculptor program ddeditor.
The Sculptor filing system uses ISAM (Indexed Sequential Access Method) techniques. In the Sculptor ISAM system, a field or fields in a file’s data record are defined as key fields. The key field(s) are indexed in a key file, which is separate from the main data file and which Sculptor can search very efficiently. Once the desired key has been located, it tells Sculptor where to read the required full data record from the main data file.
This provides extremely fast retrieval, creation, amendment and deletion of stored data. Records may be accessed randomly or in ascending or descending key sequence, and search methods are available for the access of records whose full or exact key is not known.
Sculptor keyed files are stored in a machine-independent fashion and are fully portable across the range of machines and operating systems that support Sculptor.
- File name conventions and extensions
- Key fields and data fields
- Index-only files
- File sort order
- Secondary indexes
- Data dictionaries
- Declaring, opening and closing keyed files
- Accessing keyed files
- Updating keyed files
- Record buffers
- The key = clause
- The index = clause
- File position
- File locking
- Record locking
- File property clauses
- Maximum number of records; creating big files
- File state or mode
- File report mode
- Enabling large file support on UNIX platforms
- Commands used with keyed files and record buffers
- Keyed file utilities
- kcopydir: Copying a directory structure
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