What is Oracle Call Interface?

The Oracle Call Interface (OCI) is a native C language API that allows for​ the creation of applications that can be used to manipulate data and schemas in an Oracle database. OCI supports datatypes, calling conventions, syntax, and semantics of various third-generation languages such as C, C++, COBOL, and FORTRAN.

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Applications

Since OCI is highly reliable, it is used by several Oracle tools, including SQL*Plus, Real Application Testing (RAT), and Data-Pump. Language-specific interfaces like Oracle JDBC-OCI, Oracle Precompilers, and Oracle C++ Call Interface (OCCI) drivers are also built upon the OCI. The API is used by the R language’s ROracle driver and other leading scripting language drivers such as node-oracledb, for Node.js, and PHP OCI8.

Functionality

OCI libraries provide the following functionality:

  • Accessing objects on the Oracle server using SQL.
  • Accessing, manipulating, and managing objects in the object cache by traversing pointers or REFs.
  • Converting Oracle dates, strings, and numbers to C data types.
  • Managing the size of the object cache’s memory.

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