Database Management Systems (DBMS): Introduction and Traditional File Processing, Exercises of Database Management Systems (DBMS)

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DBMS

Data processing

• Data Collection
• Recording
• Sorting
• Classifying
• Calculating
• Retrieving
• Summarizing
• Communicating

Traditional Method of Data Storage

• In the traditional approach, we used to store

information in flat files which are maintained by the file system under the operating system’s control.

• Application programs go through the file

system to access these flat files

File System Cont.

• Data used to be stored in the form of records

in the files.

• Records consist of various fields which are

delimited by a space , comma , tab etc.

• There used to be special characters to mark

end of records and end of files.

TRADITIONAL FILE PROCESSING

Data are organized, stored, and processed in independent files of data records. In the traditional file processing approach, each business application was designed to use one or more specialized data files containing only specific types of data records The business computers of 1980 were used in processing of business records and produce information using file oriented approach or file processing environment At that time that system was reliable and faster than the manual system of record keeping and processing In this system the data is organized in the form of different files. Since that system was the collection of files - so we can say it was a file-oriented system. Following terms was commonly used in this approach or the features of File oriented system.

4. File volatility ratio It is the number of records updated in a transaction file divided by total number of records. The file volatility ratio of transaction file is very high. 5. Work file A temporary file that helps in sorting and merging of records from one file to other. 6. File organization It means the arrangement of records in a particular order. There were three types of file organizations

• Sequential
• Direct
• Indexed sequential

LIMITATIONS OF FILE ORIENTED

APPROACH

1. Duplicate data / Data Redundancy

Since all the files are independent of each other. So some of the fields or files are stored more than once. Hence duplicacy is more in case of file approach. This duplication of data (redundancy) leads to higher storage and access cost. In addition it may lead to data inconsistency

LIMITATIONS OF FILE ORIENTED APPROACH

3. Separated and isolated data

To make a decision, a user might need data from two separate files. First, analysts and programmers to determine the specific data required from each file and the relationships between the data evaluated the files. Then applications could be written in a third generation language to process and extract the needed data. Imagine the work involved if data from several files was needed!

LIMITATIONS OF FILE ORIENTED APPROACH

4. Poor data security

All the files are stored in the flat form or text files. These files can be easily located and trapped because file approach, has no data security. The data as maintained in the flat file(s) is easily accessible and therefore not secure

LIMITATIONS OF FILE ORIENTED APPROACH

6. Program / Data Dependence Users and application programs need to know exactly where or how the data is stored in order to access it. In file processing system the physical formats of the files are entered in the programs. The change in file means change in program and vice versa. 7. Every operation is programmable The processing tasks like searching, editing, deletion etc should have separate programs. It means there were no functions available for these operations. DBMS have ready- made commands for such operations.

LIMITATIONS OF FILE ORIENTED APPROACH

8. Concurrency problem

It means using a same record at same time by more than one user at the same time. This problem was common in file approach but can be controlled in DBMS.

Slide 1-

Typical DBMS Functionality

• Define a database : in terms of data types, structures and constraints
• Construct or Load the Database on a secondary storage medium
• Manipulating the database : querying, generating reports, insertions, deletions and modifications to its content
• Concurrent Processing and Sharing by a set of users and programs – yet, keeping all data valid and consistent

Slide 1-

Typical DBMS Functionality

Other features:

• Protection or Security measures to prevent unauthorized access
• “Active” processing to take internal actions on data
• Presentation and Visualization of data