Please enable JavaScript.

Coggle requires JavaScript to display documents.

Relational Model - Coggle Diagram

- - - - It allows you to build complex queries and operations on the data.
- - - - Use logical conditions on tuples (rows).
      - Similar to SQL's WHERE clauses.
      - Syntax: logical formula with attributes and operators.
    - - Use variables and quantifiers (existential ∃, universal ∀).
      - It focuses on attribute values, not complete tuples.
      - Formulates logical conditions on attribute domains.
      - Both allow you to express queries logically without specifying the execution method.
- - - - Includes rows with no matches in one of the tables.
        Types: Left and Right.
    - - Includes all rows from both tables (with or without matches)
    - - Automatically joins tables by columns with the same names.
        
        It allows for more expressive queries and more specific results.
    - - Find records that meet all the conditions of another table.
    - - Calculates aggregate values: SUM, AVG, MAX, MIN, COUNT.
    - - Organizes records by one or more attributes (ASC/DESC).
- - - - Define columns, data types, and constraints.
    - - Modifies existing columns or constraints.
    - - Permanently deletes the table and its data.
    - - Add new records.
        
        It requires planning and backup to avoid data loss or inconsistency.
    - - Modifies existing values.
    - - Deletes specific records.
    - - Adjust primary keys, foreign keys, or integrity rules.
- - - - They facilitate access to complex or combined information
    - - They allow you to restrict what data can be viewed or modified
    - - They hide the actual structure of the tables.
    - - They can be used multiple times without repeating SQL code.
        
        Views are a key layer of abstraction that improves security, organization, and efficiency.
    - - Materialized views store results for quick access.
    - - They offer a coherent and organized view of the data.