Categoria: ZIM:X Database Management

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The ZIMSVLOG.ZIM file

The log file zimsvlog.zim, located in the directory pointed to by the ZIM environment variable, records all events happening with Zim Server like, its start, its end, errors, tracing, and other information. You can browse its contents using a text editor or using ZimAdmin. After some time using ZimServer, this file can become very large.…
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File Management and Distribution

Zim uses the operating system’s file management system to store entity sets, relationships, programs (source and compiled), database definitions, ZIM directories, and work files. By default, all files are stored in the same area of your file system. You can however, change the locations of the various types of files by, for example, moving the…
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How to Maintain the Integrity of a Database

A database is always considered integral unless it presents problems. This may sound a little bit funny, but the general approach, in real life, is to run an application over a database until something wrong happens. To avoid surprises, certain procedures can be preventively taken to guarantee that the database is always available. These procedures…
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Physical structure of a Zim database

The files that make up a Zim application are implemented in your operating environment’s file system. This section discusses how the various types of files are mapped onto that file system. This section looks only at the default organization. The default organization can be changed using Zim tools. Database Directory By default, Zim stores all…
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Distributing Database Files

An application is composed of a number of different types of files including directory files entity sets and relationship files application program files compiled application program files You can control where these files are located. Changing the location of files can be useful for increasing performance (locating files on the network nodes and servers where…
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Files in a Zim Application

Zim uses the operating environment’s file system to store data, programs, data dictionary definitions, configuration information, and work files. Use the ZIMFILES utility to obtain a complete list of database and document file names in your application. The following files are created by or for Zim. TYPE FILE NAME USE Database zimnnnn This file stores entity…
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Foreign Directories

Each Zim database has its own object dictionary. All objects (i.e. entity sets, forms, variables, and so on) that are described in the object dictionary are created in a Zim directory. Normally, an application developer creates the Zim directories that are used within one particular database. A foreign directory, on the other hand, is a…
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File Management

File management can be adapted to the resources available in the operating environment. To manage files efficiently, it is important to know how to control the number of files that the system has open at any one time how to estimate file space how to control the growth of a file how to pre-allocate space…
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Locks and Deadlock Conditions

Deadlocks A deadlock condition occurs when two users have to wait for each other in order to complete their respective transactions. For example, one user’s transaction needs records currently being used by a transaction started by another user. The second user’s transaction in turn requires records that the first user’s transaction is holding (while it…
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Database Backup

A well-designed database application is of no use if data and the application are not available 100% of the time. Data loss and corruption are not common in most systems, but occasional occurrences are unavoidable. Some of the events that can cause data loss include the following: Event Description User error Individual records, or even…
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