ADODB.TIsolationLevel Enumeration

TIsolationLevel values specify the level of isolation for a connection.

Pascal

TIsolationLevel = (
  ilUnspecified,
  ilChaos,
  ilReadUncommitted,
  ilBrowse,
  ilCursorStability,
  ilReadCommitted,
  ilRepeatableRead,
  ilSerializable,
  ilIsolated
);

C++

enum TIsolationLevel {
  ilUnspecified,
  ilChaos,
  ilReadUncommitted,
  ilBrowse,
  ilCursorStability,
  ilReadCommitted,
  ilRepeatableRead,
  ilSerializable,
  ilIsolated
};

File

ADODB

Description

Use TIsolationLevel values to specify the transaction isolation level for a connection.

Note: it is possible that a server will force an isolation level other than that requested.

The constants that make up the TIsolationLevel type correspond directly to the ADO IsolationLevelEnum values with the same names. These values are discussed in the Microsoft Data Access SDK help, in the topic for the IsolationLevel property of the ADO Connection object. See the SDK for additional information on the ADO constants and their effects.

The constants that make up the TADOLockType type correspond directly to the LockTypeEnum values with similar names and have the same effects. These values are discussed in the Microsoft Data Access SDK help, in the topic for the LockType property of the ADO Recordset object. See the SDK for additional information on the ADO constants and their effects.

TIsolationLevel consists of the nine constants summarized in the following table:

Isolation Level	Meaning
ilUnspecified	Server is using a an isolation level other than what was requested and the specific isolation level cannot be determined.
ilChaos	Changes from more highly isolated transactions cannot be overwritten by the current connection.
ilReadUncommitted	Uncommitted changes in other transactions are visible.
ilBrowse	Uncommitted changes in other transactions are visible.
ilCursorStability	Changes from other transactions only visible after being committed.
ilReadCommitted	Changes from other transactions only visible after being committed.
ilRepeatableRead	Changes made in other transactions not visible, but requerying can retrieve new recordsets.
ilSerializable	Transactions conducted in isolation from other transactions.
ilIsolated	Transactions conducted in isolation from other transactions.

Note: The constants ilSerializable and ilIsolated have the same effects. These two constants parallel the ADO constants adXactSerializable and adXactIsolated, which have the same effects.