3.7 Structured Query Language

• What is SQL?

  A programming language specifically used to manage database systems.
• What is a database?

  A collection of information organized for easy access and management.
• What is a relational database?

  A collection of database tables connected through relations.
• What are the key terms related to databases?

  • Table: set of data stored as rows and columns
  • Record: collection of data stored as a row
  • Field: column within a table
  • Data type: specifies type of data allowed
  • Primary key: unique ID for records
  • Foreign key: links data between tables
• What are the advantages of relational databases?

  They reduce data inconsistency and redundancy.
• What is the SQL command to search for data?

  SELECT fields FROM tableName WHERE condition ORDER BY field;
• What does the wildcard * do in SQL?

  It returns all records for a given condition.
• How do you retrieve data from multiple tables in SQL?

  By using foreign keys to link the tables.
• What is the purpose of a primary key?

  To uniquely identify records in a table.
• What is the purpose of a foreign key?

  To link data between tables.
• What is the SQL command to insert new data?

  INSERT INTO table_name (column1, column2…) VALUES (value1, value2…)
• What is the SQL command to update current data?

  UPDATE table_name SET column1 = value1 WHERE condition
• What is the SQL command to delete data?

  DELETE FROM table_name WHERE condition
• What is SQL used for?

  SQL is used to manage database systems.
• What is a database?

  A database is a collection of information organized for easy access and management.
• How is a relational database structured?

  A relational database consists of database tables organized and connected through relations.
• What is a primary key?

  A primary key is a unique ID that identifies records in a table.
• What is a foreign key?

  A foreign key is an ID used to link data between tables.
• What are the key terms related to database tables?

  • Table: a set of data stored as rows and columns
  • Record: a collection of data stored as a row in a table
  • Field: a column within a table used to store data
  • Data type: an attribute that specifies the type of data allowed
• What are the advantages of relational databases?

  • Data is structured and organized
  • Reduces data inconsistency
  • Minimizes data redundancy (copies of data in multiple tables)
• What is the SQL command to search for data?

  The command is SELECT fields FROM tableName WHERE condition ORDER BY field;
• What does the wildcard * do in SQL?

  It returns all the records for a given condition.
• What would the SQL command SELECT StudentName from Students WHERE Points < 0 ORDER BY StudentName ASC return?

  It returns "Kirstie" and "Marian" ordered in ascending order.
• How do relational databases allow data retrieval from multiple tables?

  • Data is linked through foreign keys.
  • Primary keys cannot be duplicated.
  • Foreign keys can be duplicated within the same table.
• How would you join two tables using foreign keys in SQL?

  You can use SELECT with a WHERE clause or the JOIN method.
• What is the format for inserting new data into a table?

  INSERT INTO table_name (column1, column2…) VALUES (value1, value2…)
• How would you insert a new student named Michael into the Students table?

  INSERT INTO Students (StudentName, Detail, Points, LetterSent) VALUES ("Michael", "Good work in class", 1, FALSE);
• What is the format for updating current data in a table?

  UPDATE table_name SET column1 = value1, column2 = value2… WHERE condition;
• How would you update Kirstie’s letter status to TRUE?

  UPDATE Students SET LetterSent = TRUE WHERE StudentName = "Kirstie";
• What is the format for deleting data from a table?

  DELETE FROM table_name WHERE condition;
• How would you delete Marian from the Students table?

  DELETE FROM Students WHERE StudentName = "Marian";