LinkedIn Learning – Extra material

• Relational databases –
• ANSI sql is the standard
• sql is dml data manipulation language
• sql is also a dcl data control language
• clause is a keyword for action
• predicate set peramaters
• expression – data I guess
• ACID model
  • Atomic – Even though you now know atoms can be broken down into smaller parts, the term atomic means that something can’t be broken down into smaller pieces. Here, atomicity means that the transaction behaves as one single action.
  • Consistent –
  • Isolated – actually refers to the data that is altered by other actions.
  • Durable –  requires that data changed by the transaction is written to the database.
• CRUD
  • Create
  • Read
  • Update
  • Delete

Tables

• TIMESTAMP records when something was added
• 1NF deals with repeating groups, 
• 2NF deals with key fields, specifically composite keys
• 3NF tells you that each field in a row should represent something unique about a record