Databases

Design of a Sample Food Delivery Application

• This is simplified version
  
• Lets just focus on Database
• The following questions on Database
  • Which Type of Database should i use?
  • Which Database Engine/Vendor?
  • Setup and Configuration of Databases
  • Disaster Recovery and Failure Handling

Which Type of Database should i use?

• On a broader note there are two types of Databases
  • Relational:
    • Data is stored in the form of Tables i.e. Rows and columns. Each Row represents a record for information
    • Structure is referred as schema and it is extreemly strict on schema
    • To interact with Databases we use SQL (Structured Query Language)
    • Engines:
      • Oracle
      • Microsoft SQL Server
      • mysql (mariadb)
      • Postgres
      • DB2
  • NoSQL:
    • Data is stored generally in the form of documents (other types) with no strict schema restrictions
    • There is no SQL to query the data, rather they give an API and shells
    • Engines:
      • Mongo DB
      • Couch DB
      • Cassandra
      • Gremlin
      • Neo4j

Setup and Configuration

• We need a server and
  • Install Databases
  • Configure users
• Setup for Disaster Recovery, Backup etc
• Possible issues
  • Sizing (undersize or oversize)
  • Maintenance:
    • Server
    • OS
    • Database

How cloud can help

• Here we get Database as a Service, so no installation required
• NO need to perform manual updates for os/datbase
• Replication setups are simplified and even cross location replications are possible

Terms

• Structured Data: Data which can be queried
• Failover