DBS mid semester jan 2024

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https://nptel.ac.in/courses/106106220

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https://drive.google.com/file/d/1P7MB80NMQjWG7GZvDA899N60gKPkjzLA/view

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https://drive.google.com/file/d/1OnLoSuIInoZSCtHwDM-VLzHoif5U_sOL/view

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https://drive.google.com/file/d/1O_R-0YehwV9j3I9LSEmXY0-H1jOy1YZW/view

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The Database Administrator

1. Defining the conceptual schema
2. Defining the internal schema
3. Liaising with users
4. Defining security and integrity constraints
5. Defining dump and reload policies
6. Monitoring performance and responding to changing requirements

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Four Major Components of Database Systems

1. Data - integrated and shared
2. Hardware - Secondary storage volumes, processors, main memory
3. Software - DBMS
4. Users - Application programmers, end users, database administrator

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Key to Address Transformations

1. Folding method - boundary folding, shift folding
2. MIdsquare method
3. Division - more uniform key distribution, collision and overflow
4. Digital analysis - rarely uniform -> delete, collision, alphanumeric (r = 37)
5. Radix transformation
6. Polynomial transformation
7. Random transformation - RAND(X), seed number X, key v act as the seed

Performance Evaluation of Hash Functions

• Number of overflows produced by hash functions with the keys of given file
• The average number of access per record

The expected number of overflows in division hash function is less than that produced by randomizing techniques.

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Factors Affecting Physical Organisation of Data

1. Efficient use of storage
2. Minimization of data redundancy
3. Secondary storage unit characteristics
4. Expandability
5. Recovery from dataloss
6. Data independence
7. Cost and complexity

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The Three Levels of the Architecture

1. The internal level
2. The external level
3. The conceptual level

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Client/Server Architecture

1. Server
2. Client

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Distributed Processing

1. Client
2. Server

Transparent remote access

Distributed database system

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Nicely done