Le 11/04/2015 03:53, Xiangrong Fang a écrit :
The transaction process depends upon the DBMS used. In a general way,
all DBMS execute SQL statement under the control of a transaction. Some
of the DBMS (MS SQL Server) use to have "automatic" transaction control
as default and some others (Firebird) need explicit Start and Commits.
Using Oracle definition a transaction "is a logical, atomic unit of work
that contains one or more SQL statements". I'm used to always work with
fine tuned transaction control. This way I know what the DBMS is doing
with data.
1. How to control the use of transactions in SQLDB? Sometime I do NOT
want transaction, but want the DDL/DML statement to be executed
immediately. Why sometime SQLDB's ExecSQL won't take effect if not
followed by a Commit? BTW, I tried to set tr.Active to true/false
before execute the sql, but it seems not making a difference?
Michael's comments do not need further explanation
If you want an Sql statement be executed immediately attach an
TSqlTransaction to a DB component, attach the TSqlQuery to the
transaction and enclose it between a StartTransaction and a Commit.
TR.StartTransaction;
qr.ExecSql;
TR.Commit;
The Commit matters as well
Working with DBMS since a long time, I always use the same rules: Start
a transaction, do whatever Sql statements have to be done all together,
Commit the transaction. This way I control how data is goes to and from
the databsase.
Xiangrong
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