This section describes the processes and features of the mvBase database architecture, and includes several examples to illustrate the processes described.
Database Architecture Overview
A database defines logical relationships among individual elements of data. These logical relationships include sorting, categorizing, and storing items in a manner which makes data accessible to system users.
In one sense, a database is similar to the function of the post office when sorting, storing and delivering items to customers. First, mail is sorted in a central location according to the city or town of destination. If mail is delivered to a post office in a larger city, the clerk in the delivery room may use several post office boxes with assigned numbers to store items in a manner usable to customers. Thus, regardless of the contents of these post office boxes, the box numbers direct customers to the correct location so that they can access the items they need. In this analogy, the post office boxes function as a series of files, and each box number functions as a series of pointers from one container to the next until the item of data is found:
City > Post Office > Sorting bin(s) > Post Office box(es)
This diagram depicts a chain of relationships. We can follow the pointers to reference things without really knowing what those items contain. For instance, everything in the post office or everything in each individual post office box indicates a set of things, stored in systematic fashion for accessing and updating functions.
In similar fashion, the mvBase system architecture allows us to reference a piece of data by providing a set of files and corresponding pointers. A chain of logical relationships specifies the data contained in a particular attribute, regardless of what it actually holds. The physical structure of the item is the same for each file, but its logical structure or format depends on its use.
The dictionary does more than just point to the location of data; it describes the data. It establishes symbolic references that are much more in keeping with the way people actually refer to things. For instance, a file name is a symbolic reference to a set of data stored on disk. A dictionary item contains both the physical and symbolic references to data in the data file item.
The following topics are presented in this section:
See Also
Guide to mvBase Files and Accounts Overview
Using the Terminal Control Language
Creating and Deleting Accounts
Using the BTREE File Structure System