Abeshek's Second 🧠

    2 Data Models And Query Languages

    ORM : Object-relational mapping - serves as a layere of abstraction between object oriented programming paradigms and relational database systems.

    Document models suit one-to-many relationships in data model better than relational model.

    In many-to-many and many-to-one , both relational and document model uses a reference to the data called as foreign keys in relational and document reference in document model. Using relational dbs are advantageous as they support joins.

    Use case of Document model
    • Schema flexibility
    • Better performance due to locality
    • Hetergenous data
    Use case of Relational model
    • Support for joins
    • many-to-one and many-to-many relationships is easier to represent

    SQL like languages are declarative whereas languages like C are imperative. In Declarative langauges, we just specify what we need rather than how to do it.

    Imperative : Declarative :: DOM : HTML/CSS

    Graph-Like Data Models

    • Typically used for complex many-to-many relational data model.
    Property Graphs
    • Both vertices and edges are similar to tables in relational dbs.

    property-graphs.png

    Cypher Query Language

    Insertion

    cypher-insertion.png

    Query ^dd6cdc

    cypher-query.png

    Triple Stores and SPARQL

    Information is stored in terms of (subject, predicate, object).
    Subject ---> Object , predicate is the info on the edge.

    triple-stores.png

    Same 2 Data Models and Query Languages > ^dd6cdc in sparkQL

    sparql.png