Data.SqlExpr.TTransIsolationLevel

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Delphi

TTransIsolationLevel = (xilREADCOMMITTED, xilREPEATABLEREAD, xilDIRTYREAD, xilCUSTOM);

C++

enum DECLSPEC_DENUM TTransIsolationLevel : unsigned char { xilREADCOMMITTED, xilREPEATABLEREAD, xilDIRTYREAD, xilCUSTOM };

Properties

Type Visibility Source Unit Parent
enum public
Data.SqlExpr.pas
Data.SqlExpr.hpp
Data.SqlExpr Data.SqlExpr

Description

This enumerated type (in C++) or type (in Delphi) identifies degree to which transactions are isolated from each other.

The following table describes the possible values.



Element Description

xilDIRTYREAD

Current transaction sees all changes made by other transactions, even if they have not yet been committed. This option is not available for the Oracle driver.

xilREADCOMMITTED

Current transaction sees only changes that have been committed, but can receive an inconsistent view of the data if additional changes are committed before the transaction ends.

xilREPEATABLEREAD

Current transaction is guaranteed a consistent view of the data, which includes only changes committed by other transactions at the start of the transaction.

xilCUSTOM

Current transaction uses a database-specific isolation level. When the eConnTxnIsoLevel option is xilCUSTOM, the transaction descriptor gives the actual isolation level. This is not currently supported by any drivers, but allows future drivers the ability to expand the number of isolation levels.