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4GL language

In Mitrol, a database is a network of interrelated files serving as a common repository for data that can be used by one or more applications. Our technology includes a comprehensive language that permits the definition and redefinition of all database elements (the data definition language (DDL)) and also that allows data in a given database to be stored, retrieved and processed (the data manipulation language (DML)). These languages operate during a Mitrol session, which is our name for the processing environment created by running the Mitrol core program. A Mitrol session allows one or more users to process data stored in a single Mitrol database.

The Mitrol DML and DDL languages are constructed in a manner similar to each other. A command or statement is called Request, which is a sentence of code that starts with a Verb and is followed by a series of Clauses and Phrases.

A production application needs a facility for packaging Requests into individual transactions or reports. Special purpose files, that we will call Macros, can be created that contain compiled code to run a specific application-oriented operation. A Mitrol application can thus be thought of as a library of Macros that collectively allow a user group to perform all the necessary operations and queries they require on a Mitrol database. Mitrol's 4GL is a verb driven language. Requests are written using one or more of the verbs.

Database group requests are used within a special environment known as Database Group to define the permanent physical and logical structure of the database. You write these requests with the data definition language (DDL) component of Mitrol. Database group requests use the following verbs to define, change and display the characteristics of all database elements (files, fields, relations, macros and users):

  • DEFINE, to define an element
  • REDEFINE, to modify its definition
  • DISPLAY, to print its characteristics
  • REMOVE, to remove its definition from the database
  • GENERATE, to precompile MITROL transactions
  • REGENERATE, to refresh the generated execution tables in the request when changes to the schema invalidate the old execution tables.Mitrol stamps the schema and changes so that it is impossible to run out-of-date and potentially incompatible code.

Display-update (DUPD) requests, are used to display and update the data in your database. You write these with the data manipulation language (DML) component of MITROL. These may be defined to the database as permanently stored macros. The display up-date verbs are:

  • ASSEMBLE, to create records in an indirect file owned by a direct file through two relations (a tree structure). It is primarily used to create bills of material.
  • CHART, to access the IBM Interactive Chart Utility (GDDM) to produce graphic images.
  • CREATE, to establish new records or create relationships between existing records.
  • DELETE, to remove records or break relational links.
  • PRINT, to generate reports.
  • SET, to establish values for fields in existing records.
  • UPDATE, to create, delete, or modify records.

In addition, the Mitrol language includes a variety of application-specific verbs. Each of these verbs replaces the hundreds (sometimes thousands) of lines of programming needed to perform the same tasks in systems using COBOL or SQL languages. These are:

  • EXPLODE, to produce a single-level or multiple-level bill of material explosion.
  • WHERE-USED, to produce a single level or multi-level bill of material implosion.
  • KIT, to generate a pick list of components required to manufacture a specified quantity of an assembly
  • PEG, to print the PEG and LOAD PEG reports.
  • PLAN, to perform a full Material Requirements Plan and/or Capacity Requirements Plan scheduling material purchases and production activity.
  • SUMMARIZE, to explode an assembly or group of assemblies through all product structure levels summarising the required quantities of each component part.
  • TOTALIZE, to perform a bill of material roll up. This is primarily used to calculate a costed bill of material or accumulated lead times.

Finally, the Mitrol language simplifies updating and enhancing applications because its application code is independent of the physical database structure. Therefore, it is generally not necessary to change existing programs when new data elements are added or existing elements modified. As your requirements change and grow, your investment in application code is preserved.



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© 2000-2003 Teamco Systems Innovation, email: info@mitrol.com.

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