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SLR 10 Data (Data bases (relational) (Normalisation (0NF->1NF->…

- - - - 0NF - data is not arranged in and efficient way.
      - 1NF - Data is arranged a bit more efficiently
      - 2NF -
      - 3NF -
      - Improving data so that it can be searched, sorted or filtered
      - To get to 1NF:
        
        Eliminate duplicate colums
        
        Get rid of any groups of repeating data
        
        Identify the Primary key
        
        Separate out any attributes which are not "atomic" into separate
      - To get to 2NF:
        
        Check data is already 1NF
        
        Remove any partial dependencies:
        
        ∙A partial dependency means that one or more of the attributes depends on only part of the primary key.
        
        ∙This can only occur if the primary key is a composite key.
        
        ∙If we find a partial dependency split the table on that attribute and move into a separate table
        
        "Fix" any Many-to-Many relationships you discover
    - - A combination of two or more columns in a table that can be used to uniquely identify each set of data