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    • #913
      Abhishek TyagiAbhishek Tyagi
      Keymaster

      1.What is the primary added value of relational databases over flat files?
      ==>Ability to scan large amounts of data quickly

      2.What is the purpose of a primary key?
      ==>To look up a particular row in a table very quickly

      3.Which of the following is NOT a good rule to follow when developing a database model?
      ==>Use a person’s email address as their primary key

      4.If our user interface (i.e., like iTunes) has repeated strings on one column of the user interface, how should we model this properly in a database?
      ==>Make a table that maps the strings in the column to numbers and then use those numbers in the column

      5.Which of the following is the label we give a column that the “outside world” uses to look up a particular row?
      ==>Logical key

      6.What is the label we give to a column that is an integer and used to point to a row in a different table?
      ==>Foreign key

      7.What SQLite keyword is added to primary keys in a CREATE TABLE statement to indicate that the database is to provide a value for the column when records are inserted?
      ==>AUTOINCREMENT

      8.What is the SQL keyword that reconnects rows that have foreign keys with the corresponding data in the table that the foreign key points to?
      ==>JOIN

      9.What happens when you JOIN two tables together without an ON clause?
      ==>The number of rows you get is the number of rows in the first table times the number of rows in the second table

      10.When you are doing a SELECT with a JOIN across multiple tables with identical column names, how do you distinguish the column names?
      ==>tablename.columnname

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