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Java Database Connectivity (JDBC)

  • an API for client-side access to a database
  • specifically RDBMS focused

Basic Flow​

Mount Driver -> Create Connection -> Execute SQL -> Commit / Rollback -> Close Connection

Features​

Universal Data Access​

  • hot swappable
  • standard SQL
  • JDBC drivers available
  • can run the same code against 2 different databases in theory

Exceptions​

  • all JDBC operations throw a SQLException
  • name exception
    • you have to catch it or throw it
  • standardized SQLSTATE code is available
  • ErrorCode is available but is vendor specific in most cases

Terminology of JDBC​

Connections​

  • DriverManager
    • a class that interacts with the driver for creating connections
  • DataSource
    • a modern class that interacts with the driver for creating connections
  • Connection
    • a class that the developer interacts with that manages the actual communication between the client and the server

Executions​

  • Statement
    • the representation SQL to be executed against the database
  • ResultSet
    • the response from the database in a logical tabular form
  • PreparedStatement
    • an extension of statement that is used for precompiled statements (with inputs)
  • CallableStatement
    • an extension of PreparedStatement that references stored procedures in the database (with inputs and outputs)

Transactions​

  • Auto-commit
    • a function of a database driver where each statement is immediately readable by all processes once executed in the RDBMS
  • Transaction
    • a series of statements that must be executed completely or not at all before any other process can read them
  • Rollback
    • a mechanism by which all statements of a transaction are removed from the database such that it appears to all current and future processes as never having occurred