>Have someone experienced problemns with multiple field indexes, like: field1 + dtos(field2) + str(field3)... Problemns like: slow indexes, corrupted indexes, etc...
>
>I need that for primary key.
>
>Cause I have developed a database that have until 6 fields concatenated on one single tag, and the tables will have a lot of records (1 million+).
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>Any experience will be apreciated.
>Thanks.

This isn't a good idea for a primary key. You should look at a surrogate key for a PK. There is an article on my web site that explains how to do this.