databases - organized collection of data that's accessible, manipulable, and analyzable.

• data types include authentication credentials (usernames/passwords)
• also includes content like posts, comments, likes

2 Primary Database Types

1. relational databases (SQL)
   1. structured data format
      1. user data example:
      2. first_name, last_name, email, username password
      3. organized entry for each new user
      4. row/column storage
      5. connects multiple tables (user order_history)
2. non-relational databases (NoSQL)
   1. stores data in non-tabular format

 {
    _id: ObjectId("4556712cd2b2397ce1b47661"),
    name: { first: "Thomas", last: "Anderson" },
    date_of_birth: new Date('Sep 2, 1964'),
    occupation: [ "The One"],
    steps_taken : NumberLong(4738947387743977493)
}

Two types of keys:

1. Primary Keys: ensure unique data in a column.
   • Provides unique ID for each record
   • Column chosen as primary key; id typically used for uniqueness
   • Only 1 primary key column allowed per table
2. Foreign Keys: Column in one table that references another table
   • author_id in Books table → links to id in author table
   • Enable relationships between tables in relational databases
   • Multiple foreign key columns allowed in a table

Databases are managed via Database Management Systems (DBMS)

• interfaces between users and databases
• enables data retrieval, updates and management
• examples: MySQL, MongoDB, Oracle, Maria DB

SQL (Structured Query Language) queries, defines and manipulates relational database data

Database Statements