Database Services

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A database provisions information in a format that can be read and updated through some type of query language.

• two main types of databases:
  • relational databases
    • store information in tables with rows (records) and columns (fields)
    • relationships between data fields in different tables is created using key fields that uniquely identify each record
    • operated using Structured Query Language (SQL)
      • defines commands to retrieve information or to change it
        • e.g., SELECT or UPDATE
      • implemented in relational database management systems (RDBMS) platforms by several different vendors
        • RDBMS provides management tools and a GUI to operate the database
        • a remote access protocol allows:
          • a client to connect to the database server over the network
          • replication traffic to move between database servers
            • is a means of synchronizing the data held on each server
        • each RDBMS uses a different TCP port:
          • TCP/1521: Oracle’s remote data access protocol SQL*Net
          • TCP/1433: Microsoft SQL Server
          • TCP/3306: MySQL
            • open source
            • MariaDB platform uses same port
              • forked from MySQL
          • TCP/5432: PostgreSQL
            • open source
        • these are the principle ports
          • RDBMS is likely to use other TCP or UDP ports for other functions
        • ports are insecure by default
          • RDBMS server can be installed with a certificate and configured to enable TLS transport encryption
          • connection is made over the same port
          • server or client can be configured to require encryption
            • can drop the connection if valid security profile is not available
          • client can also be installed with a certificate and the server configured to refuse connections from clients without a valid certificate
    • NoSQL (not only SQL) databases
      • rather than highly structured relational tables, NoSQL data can use a variety of formats
        • E.g., key-value pairs, wide columns (rows do not have to have the same set of fields)
      • typically accessed using an API over HTTPS

Info

• All RDBMS platforms support NoSQL datastores
• are also dedicated NoSQL platforms
  • e.g., MongoDB, Amazon DynamoDB, CouchDB