# 7.3. ODPI-C Structure dpiAppContext

This structure is used for passing application context to the database during the process of creating standalone connections. These values are ignored when acquiring a connection from a session pool or when using DRCP (Database Resident Connection Pooling). All values must be set to valid values prior to being used in the dpiConnCreateParams structure and must remain valid until the execution of `dpiConn_create()` completes. Values set using this structure are available in logon triggers by using the sys_context() SQL function.

const char *dpiAppContext.namespaceName

  Specifies the value of the “namespace” parameter to sys_context(). It is expected to be a byte string in the encoding specified in the dpiConnCreateParams structure and must not be NULL.

uint32_t dpiAppContext.namespaceNameLength

  Specifies the length of the `dpiAppContext.namespaceName` member, in bytes.

const char *dpiAppContext.name

  Specifies the value of the “parameter” parameter to sys_context(). It is expected to be a byte string in the encoding specified in the dpiConnCreateParams structure and must not be NULL.

uint32_t dpiAppContext.nameLength

  Specifies the length of the `dpiAppContext.name` member, in bytes.

const char *dpiAppContext.value

  Specifies the value that will be returned from sys_context(). It is expected to be a byte string in the encoding specified in the dpiConnCreateParams structure and must not be NULL.

uint32_t dpiAppContext.valueLength

  Specifies the length of the `dpiAppContext.value` member, in bytes.