Unit 4
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Understand the difference between lossless and lossy compression
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Explain run-length encoding and dictionary-based compression
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Define symmetric and asymmetric encryption
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Understand how and why hashing may be used to encrypt data
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Explain the concept of a relational database
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Define the terms flat file, entity, attribute, primary key, foreign key, secondary key, entity-relationship modelling, referential integrity
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Produce an entity-relationship model for a simple scenario involving multiple entities
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Explain the concept of a relational database
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Normalise relations to third normal form
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Understand why databases are normalised
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Be able to use SQL to retrieve data from multiple tables of a relational database
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Be able to interpret and modify SQL
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Be able to use SQL to define a database table
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Be able to use SQL to update, insert and delete data
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from multiple tables of a relational database
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Describe methods of capturing, selecting, managing and exchanging data
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Describe what is meant by transaction processing and ACID (Atomicity, Consistency, Isolation, Durability)
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Describe what is meant by record locking and why it is necessary for a multi-user database
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Describe what is meant by redundancy