# 7.6. ODPI-C Structure dpiConnCreateParams

This structure is used for creating connections to the database, whether standalone or acquired from a session pool. All members are initialized to default values using the `dpiContext_initConnCreateParams()` function. Care should be taken to ensure a copy of this structure exists only as long as needed to create the connection since it can contain a clear text copy of credentials used for connecting to the database.

dpiAuthMode dpiConnCreateParams.authMode

  Specifies the mode used for authorizing connections. It is expected to be one or more of the values from the enumeration dpiAuthMode, OR’ed together. The default value is DPI_MODE_AUTH_DEFAULT.

const char *dpiConnCreateParams.connectionClass

  Specifies the connection class to use when connecting to the database. This is used with DRCP (database resident connection pooling) or to further subdivide a session pool. It is expected to be NULL (meaning that no connection class will be set) or a byte string in the encoding used for CHAR data. The default value is NULL.

uint32_t dpiConnCreateParams.connectionClassLength

  Specifies the length of the `dpiConnCreateParams.connectionClass` member, in bytes. The default value is 0.

dpiPurity dpiConnCreateParams.purity

  Specifies the level of purity required when creating a connection using a connection class. It is expected to be one of the values from the enumeration dpiPurity. The default value is DPI_PURITY_DEFAULT.

const char *dpiConnCreateParams.newPassword

  Specifies the new password to set when creating a connection. This value is only used when creating a standalone connection. It is expected to be NULL or a byte string in the encoding used for CHAR data. The default value of this member is NULL. If specified, the password for the user is changed when the connection is created (useful when the password has expired and a session cannot be established without changing the password).

uint32_t dpiConnCreateParams.newPasswordLength

  Specifies the length of the `dpiConnCreateParams.newPassword` member, in bytes. The default value is 0.

dpiAppContext *dpiConnCreateParams.appContext

  Specifies the application context that will be set when the connection is created. This value is only used when creating standalone connections. It is expected to be NULL or an array of dpiAppContext structures. The context specified here can be used in logon triggers, for example. The default value is NULL.

uint32_t dpiConnCreateParams.numAppContext

  Specifies the number of elements found in the `dpiConnCreateParams.appContext` member. The default value is 0.

int dpiConnCreateParams.externalAuth

  Specifies whether external authentication should be used to create the connection. If this value is 0, the user name and password values must be specified in the call to `dpiConn_create()`; otherwise, the user name and password values must be zero length or NULL. The default value is 0.

void *dpiConnCreateParams.externalHandle

  Specifies an OCI service context handle created externally that will be used instead of creating a connection from scratch. The default value is NULL. Note that this connection depends on the external handle remaining valid for the lifetime of this connection. It is also important to ensure that the last reference to this connection is released before the external service context handle and environment handle are destroyed. Unlike regular connections, no attempt is made to rollback any outstanding transactions or close any open statements, objects and LOBs when the last reference to this connection is released, since attempts to do so after the external service context handle and environment are destroyed may result in crashes and other undesirable behavior.

dpiPool *dpiConnCreateParams.pool

  Specifies the session pool from which to acquire a connection or NULL if a standalone connection should be created. The default value is NULL. If the method `dpiPool_acquireConnection()` is being called, this value is ignored.

const char *dpiConnCreateParams.tag

  Specifies the tag to use when acquiring a connection from a session pool. This member is ignored when creating a standalone connection. If specified, the tag restricts the type of session that can be returned to those with that tag or a NULL tag. If the member `dpiConnCreateParams.matchAnyTag` is set, however, any session can be returned if no matching sessions are found.

  The value is expected to be NULL (any session can be returned) or a byte string in the encoding used for CHAR data. The default value is NULL. If specified, the value should be one or more properties (specified in the form key=value) separated by semicolons.

uint32_t dpiConnCreateParams.tagLength

  Specifies the length of the `dpiConnCreateParams.tag` member, in bytes. The default value is 0.

int dpiConnCreateParams.matchAnyTag

  Specifies whether any tagged session should be accepted when acquiring a connection from a session pool, if no connection using the tag specified in the `dpiConnCreateParams.tag` is available. This value is only used when acquiring a connection from a session pool. The default value is 0.

const char *dpiConnCreateParams.outTag

  Specifies the tag of the connection that was acquired from a session pool, or NULL if the session was not tagged. This member is left untouched when creating a standalone connection and is filled in only if the connection acquired from the session pool was tagged. If filled in, it is a byte string in the encoding used for CHAR data.

uint32_t dpiConnCreateParams.outTagLength

  Specifies the length of the `dpiConnCreateParams.outTag` member, in bytes.

int dpiConnCreateParams.outTagFound

  Specifies if the connection created used the tag specified by the `dpiConnCreateParams.tag` member. It is only filled in if the connection was acquired from a session pool and a tag was initially specified.

dpiShardingKeyColumn *dpiConnCreateParams.shardingKeyColumns

  Specifies an array of dpiShardingKeyColumn structures which are used to identify which database shard should be connected to. The number of elements in the array is assumed to contain at least `dpiConnCreateParams.numShardingKeyColumns` elements.

uint8_t dpiConnCreateParams.numShardingKeyColumns

  Specifies the number of elements in the array of sharding key columns found in the member `dpiConnCreateParams.shardingKeyColumns`.

dpiShardingKeyColumn *dpiConnCreateParams.superShardingKeyColumns

  Specifies an array of dpiShardingKeyColumn structures which are used to identify which database shard should be connected to. The number of elements in the array is assumed to contain at least `dpiConnCreateParams.numSuperShardingKeyColumns` elements.

uint8_t dpiConnCreateParams.numSuperShardingKeyColumns

  Specifies the number of elements in the array of sharding key columns found in the member `dpiConnCreateParams.superShardingKeyColumns`.

int dpiConnCreateParams.outNewSession

  Specifies if the connection created was newly created by the session pool and has never been acquired from the pool (1) or not (0). It is only filled in if the connection was acquired from a session pool.