7 Database types

7.1 Database Types according to data structure they store

Relational DBMS
Key-value stores
Document stores
Time Series DBMS
Graph DBMS
Search engines
Object oriented DBMS
RDF stores
Vector DBMS
Wide column stores
Multivalue DBMS
Spatial DBMS
Native XML DBMS
Event Stores
Content stores
Navigational DBMS
Columnar

7.2 Relational databases

Even though there are a lot of databases types, the relation databases will be the focus of this course. The so-called nosql and other types of databases, will not be covered.

7.3 Database types according to architecture

Server-client
file based
in memory

7.4 Server Client

flowchart LR
    subgraph Client
        C[Client Application]
    end

    subgraph Server
        S[Server]
        DB[(Database)]
    end

    C -- "1 Send request" --> S
    S -- "2 Query" --> DB
    DB -- "3 Return data" --> S
    S -- "4 Process data" --> S
    S -- "5 Send response" --> C

7.5 File based

In file based architecture, a local file is used as database. There is no server, everything is done in the client computer. Sqlite and Microsoft Access are well known file based databases.

7.6 In memory

Everything is stored in the memory. Thus when the client process ends, database contents are also lost. In memory databases are used for testing and caching. Sqlite could work as in memory database.