Setting INDEXNAME using MYSQL
lazarus / 16-Databases

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majlumbo · 2009-01-12 15:25

I have attempted to set the INDEXNAME property of the TSQLQUERY
component to the name of an already defined unique index on my MYSQL
db.  As soon as I finish typing the name of my index, it automatically
gets reset to DEFAULT_ORDER. 

I previously used an order by in the sql statement, but found that
after inserting a new record, the list is not in index order until I
close and re-open the query, prompting the need to use the index
instead.

Any ideas?

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Loesje · 2009-01-15 11:01

The indexname property can not be used to select an index on your
server. You can use it when you define a local index.

Easiest is to assign the fields on which you want to sort to the
'indexfieldnames' property. That will generate a temporary index based
on those fields. Else you have to create an index yourself. (The
indexdefs property) But Lazarus doesn't have an editor to do that, I
just saw. so you have to do it with code...

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majlumbo · 2009-01-15 14:13

Thanks Loesje,

Seems to work now.  Is there any benefit to maintaining the MySQL
server defined index?

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Loesje · 2009-01-18 17:56

Yes, it can make joins faster, and the result when you use 'order by'.

The TSQLQuery also had a ServerIndexDefs-property. This is used to
obtain the primary key, which is used when updating data. (with
ApplyUpdates)