IsolationLevels Property

The IsolationLevels property is a bit mask, that indicates the level of transaction support.

Applies to objects: Connection, Database.

Syntax

[[Let] RetVal = ] object.IsolationLevels

The Transactions property syntax has these parts:

Part Description
object Required. A reference to an instance of the object.
RetVal Optional. A Long type variable.

Remarks

The following situations may occur when using transactions:
Dirty Read. Transaction 1 changes a row. Transaction 2 reads the changed row before transaction 1 commits the change. If transaction 1 rolls back the change, transaction 2 will have read a row that is considered to have never existed.
Nonrepeatable Read. Transaction 1 reads a row. Transaction 2 updates or deletes that row and commits this change. If transaction 1 attempts to reread the row, it will receive different row values or discover that the row has been deleted.
Phantom. Transaction 1 reads a set of rows that satisfy some search criteria. Transaction 2 generates one or more rows (through either inserts or updates) that match the search criteria. If transaction 1 reexecutes the statement that reads the rows, it receives a different set of rows.

The IsolationLevels property may contain a combination of the following values:
cdbTransReadUncommited - Dirty reads, nonrepeatable reads, and phantoms are possible.
cdbTransReadCommited - Dirty reads are not possible. Nonrepeatable reads and phantoms are possible.
cdbTransRepeatableRead - Dirty reads and nonrepeatable reads are not possible. Phantoms are possible.
cdbTransSerializable - Transactions are serializable. Serializable transactions do not allow dirty reads, nonrepeatable reads, or phantoms.

If equal to 0 - transactions are not supported.

This property is Read-Only.

Example

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See Also

Connection Object, Database Object, Transactions Property, BeginTrans Method.