DataPlus API Library
Today, companies around the world are making DataEase a relational database standard. The DataPlus Library for DataEase is an Application Programming Interface (API) that opens the database engine of DataEase to the programming community.
The DataPlus Library can also be used to process both DataEase and non-DataEase data.
Programmers creating custom applications can now integrate specialist functionality and data structures into their applications of DataEase.
An Applications Programming Interface
The DataPlus Library provides developers with an Application Programming Interface (API) of more than 110 functions.
DataPlus comes in the form of a library that can be linked with any programs you create. Because DataPlus is a library, applications written with DataPlus can be very small - the size of your application depends on the number of lines of code and the number of DataPlus library calls.
DataPlus provides an API that lets you:
. Read from, and write to, DataEase tables.
. Support DataEase features such as password protection, encrypted tables, searching and error handling.
. Create stand-alone applications or applications used as an extension of DataEase.
DataPlus allows you to use new techniques for importing data into DataEase tables, such as through serial communications, by downloading from mainframes, or from external devices that could not otherwise be reached from DataEase DQL.
With DataEase and DataPlus, you can choose which parts of your application are best suited for DataPlus and which are best for interactive DataEase.
The Relationship between DataEase DQL and DataPlus
The DataEase Query Language (DQL) and DataPlus each have their own spheres of functionality. There are tasks that can be done in DQL that cannot be done in DataPlus. Likewise, there are things that can be done in DataPlus that cannot be done in DQL. The solution is not to choose between one tool or the other, but to use each for the job at which it is best.
DQL is an interpreted high-level language tightly integrated into the DataEase interactive environment. It provides a scripting capability woven into the interactive interface in conjunction with procedural capabilities. DQL provides access to many high-level special-purpose capabilities in DataEase such as Query-by-Example (QBE) and multi-table tables. Because DQL is interpreted and provides a high degree of interaction, it's an ideal language for rapid prototyping, as well as for some full-scale production of multi-user database applications.
DataPlus Design Philosophy
The primary objective of DataPlus is to shield the programmer from the internal structure of DataEase. This is achieved by creating a data dictionary that describes the characterisics of a database, its tables and fields, e.g. record and field lengths, field types, etc.
Table records are stored in internal buffers and no knowledge of the record layout is assumed or needed.
Data is inserted into, and extracted from, the internal buffers by transfer functions that are given the address of working storage areas in the programmers domain, and a target field of a table by its name . i.e. there is no need for a programmer to know where a field is located in a table record - changes can be made to the underlying database structure by a Database Administrator without having to re-write and compile all the application programs.
All indices are automatically updated without the need for programmer intervention.
The programmer is notified of any data integrity violations, e.g. required fields are blank, duplication of all the unique fields, etc.
Straightforward Program Structures
Using DataPlus is as easy as using the standard Input and Output routines supplied as library functions by your normal compiler. Programs can be developed in a standard block-structured way by recognising that the same constraints that apply to standard file processing apply to DataPlus functions, e.g. tables must be opened before they can be read or written.
As with standard file functions, there is a concept of a current pointer in a table, only in the case of DataPlus, that is extended to each index file on indexed fields of a table. Whenever records are read or written, the index pointers are updated. This allows the programmer to process a file sequentially, either by the saved order of data in a table, or by the sequence dictated by the specification of an indexed field of a table.
Records in a table can be read randomly by using the relative record number of a table, or by using the expected value of an indexed field in the required record of a table. They can also be processed sequentially as described in the previous paragraph. Essentially, DataPlus mirrors the functionality available to the user of DataEase when sitting at the interactive screen (the DataEase equivalent of Library functions are included in brackets after the title of each function). There are two writing functions, DP_save_record which appends a new record to the end of a table, and DP_modify_record which updates the record at the current table pointer. In both cases, pointers and indexes are updated automatically.
Download a demonstration and evaluation version of DataPlus.
(This is a VERY old demonstration that will be updated shortly)
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