ORACLE OCI

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ORACLE OCI

• Oracle Call Interface for C and C

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Basic Program Structure

• Initialize the OCI programming environment and
  processes.
• Allocate necessary handles, and establish a
  server connection and a user session.
• Issue SQL statements to the server, and perform
  necessary application data processing.
• Free statements and handles not to be reused or
  re-execute prepared statements again, or prepare
  a new statement.
• Terminate user session and server connection.

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OCI Data Structures

• Handles
• opaque data structures
• Similar to file ids in c

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Sample OCI Handles
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Environment Handle

• The environment handle defines a context in which
  all OCI functions are invoked. Each environment
  handle contains a memory cache, which allows for
  fast memory management in a threaded environment
  where each thread has its own environment

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OCIInitialize()

• Must be called before any other OCI call.
• Mode Parameter
• OCI_DEFAULT
• OCI_THREADED
• OCI_OBJECT

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OCIEnvInit()
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Single-User, Single Connection

• OCILogon(envhp, errhp, svchp, "scott", nameLen,
  "tiger", passwdLen, "oracle8", dbnameLen)
• evhp environment handle
• errhp error handle