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Purpose
Returns or assigns an integer value indicating the ODBC transaction isolation level.
The following definitions and behaviors are defined in ODBC:
Dirty Read |
Transaction1 modifies a row and Transaction2 reads the modified row before Transaction1 commits the change. If Transaction1 rolls back the change, Transaction2 will have read a row that should have never existed. |
Nonrepeatable Read |
Transaction1 reads a row and Transaction2 updates or deletes that row and commits this change. If Transaction1 rereads the row, it will receive different values or discover that the row no longer exists. |
Phantom |
Transaction1 reads a set of rows that satisfy some search criteria. Transaction2 inserts a row that matches the search criteria. If Transaction1 re-executes the query that reads the rows, it receives a different set of rows. |
Syntax
DBConnection.Txnlsolation [= Constant]
Constant |
Possible values: |
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SQL_TXN_READ_UNCOMMITTED |
Dirty reads, nonrepeatable reads, and phantoms are possible. |
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SQL_TXN_READ_COMMITTED |
Dirty reads are not possible. Nonrepeatable reads and phantoms are possible. |
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SQL_TXN_REPEATABLE_READ |
Dirty reads and nonrepeatable reads are not possible. Phantoms are possible. |
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SQL_TXN_SERIALIZABLE |
Transactions are serializable. Dirty reads, nonrepeatable reads, and phantoms are not possible. |
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