delphi and mysql

[christophermoore]

Hi,

We will be using delphi and mysql in a multiuser environment. Am i right in saying that if we set all of our tables to 'Type = InnoDB' that we will be assured of data integrity through transaction control?

We need to ensure that users at different terminals do not write over records that someone has just changed....

Many thanks

Chris

 

[footpad]

Chris,

MySQL's online manual for CREATE TABLE (

http://www.mysql.com/doc/en/CREATE_TABLE.html)

contains a table that compares the available types.

According to that page, InnoDB is a transaction safe format that supports row level locking. This may or may not be appropriate; it depends on how you want to handle the concurrency issue.

While the row level locking is tempting, there are other risks. Most C/S projects use optimistic, rather than pessimistic locking and there are well-known (and documented) strategies for handling changes.

Indeed, Delphi contains several components that let you handle situation where the record has changed underneath you.

Check out

http://thedelphimagazine.com/samples/1540/1540.htm

as a starter and then scan the white papers at

http://community.borland.com/all/0,1435,c|7|13,00.html

for more specific information.

Hope this helps...

-- Lance