Limit on number of queries from CGI or PHP (security)

Hi,

Is there any way I can restrict number of queries to
only one? Here's the problem:

If PHP script gets some data as input from user, and
PHP scripts tries to put this data into Postgresql,
what's keeping the user to modify the data in way to
have postgresql execute two queries.

So instead of some PHP script generating query like
"select * from table where text='some text' or id=1",
some malicious user could make it generate "select *
from table where text='some text' or id=1;delete from
table"

Thanks,
Rikul

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