Execute query only if it is select statement. How?

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Execute query only if it is select statement. How?

i have string that contins sql selements if that statement is not update query execute the query other wise block the execution

Posted 6-Dec-11 1:13am

Aneesh M

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Michel [mjbohn] · Answer 1 · 2011-12-06T01:19:00

Solution 2

Sounds dangerous! These restrictions should be set at database level.
Don't do it this way.

Posted 6-Dec-11 1:19am

Michel [mjbohn]

Comments

#realJSOP 6-Dec-11 7:58am

This is not a permission or privilege issue. He obviously has some bizarre reason for writing this kind of code. Since he's not sharing it with us, I don't see how you can suggest this.

Michel [mjbohn] 6-Dec-11 8:38am

Please see my comment at solution 4.

Wendelius · Answer 2 · 2011-12-06T01:39:00

Solution 5

There's always a risk that the statement contains DML thus affecting the database. The proper way to ensure that no harm is done is to grant only necessary privileges to the user executing the statement. More info, see: GRANT[^].

Posted 6-Dec-11 1:39am

Wendelius

#realJSOP · Answer 3 · 2011-12-06T01:21:00

Solution 4

C#

if (yourquery.Trim().ToUpper().StartsWith("SELECT"))
{
    // execute the query
}

Posted 6-Dec-11 1:21am

#realJSOP

Comments

Robert Rohde 6-Dec-11 7:34am

Even though your solution is "a bit" better than from Uma and Derek this is still dangerous. Just because it starts with "select" it doesn't mean that it cannot modify the database.
Like mjbohn said this should be made with a specialized database user with read only access rights.

#realJSOP 6-Dec-11 7:56am

He wanted a solution in C#. I'm assuming his query is properly formed and that he's done everything else he needs to do to make it work. I don't have the time to speculate as to whether he should do it this way or not, and I certainly wouldn't do it this way myself. That's no reason to vote my answer down.

Michel [mjbohn] 6-Dec-11 8:17am

I agree with your perspective. And there's no reason to down vote. But isn't it important to alert OP that he's (probably) going to do dangerous things?

Robert Rohde 6-Dec-11 15:22pm

"I'm assuming his query is properly formed and that he's done everything else he needs to do to make it work" sounds a bit naive. If he asks such a simple question do you really think he knows what he's doing...?

Derek Henderson · Answer 4 · 2011-12-06T01:18:00

Solution 1

Heres the C# solution not sure if you wanted TSQL or C#

C#

if(yourString.ToUpper().Contains("SELECT") && !yourString.ToUpper().Contains("UPDATE"))
{
    execute the query ....
}

Posted 6-Dec-11 1:18am

Derek Henderson

Updated 6-Dec-11 1:22am

v2

Comments

Michel [mjbohn] 6-Dec-11 7:23am

Try this string:"drop database xy; -- select"
Might be fatal

uspatel · Answer 5 · 2011-12-06T01:20:00

Solution 3

try this

C#

 string ss = "select * from tablename";
        int c = ss.IndexOf("select");
if(c>=0)
{
..executeablecode
}
else
{
return;
}

Posted 6-Dec-11 1:20am

uspatel

Comments

Michel [mjbohn] 6-Dec-11 7:23am

Try this string:"drop database xy; -- select"
Might be fatal