RE: [PHP] sql query successful

[Mark Roedel]

 -Original Message-
 From: Tyler Longren [mailto:[EMAIL PROTECTED]]
 Sent: Wednesday, July 18, 2001 1:25 PM
 To: php-general
 Subject: [PHP] sql query successful
 
 
 I've been writing database enabled site for quite a while 
 now.  One thing I have never figured out it how to determine
 if a sql query is successful.
 
 This works:
 if ($connection = mysql_connect(host,username,password)) {
 print Successful connection:
 }
 else {
 print No connection;
 }
 
 But this won't work:
 
 if ($sql = mysql_query(SELECT * FROM table ORDER BY rand())) {
 print SQL executed successfully.;
 }
 else {
 print SQL not executed successfully.;
 }

In what way doesn't this work?

The above code should tell you that the query was properly formed and
error-free, and was cheerfully accepted and processed by the database
server.  (You don't get much more successful than that...)

If what you're really looking for is whether there were any rows
returned by the query, then you'll want to look into the
mysql_num_rows() function.


---
Mark Roedel ([EMAIL PROTECTED])  ||  There cannot be a crisis next week.
Systems Programmer / WebMaster  ||   My schedule is already full.
 LeTourneau University  ||-- Henry Kissinger


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RE: [PHP] sql query successful

[Hoover, Josh]

I believe you should use the error function for the database you're using to
check for failed queries.  If you're using MySQL (which it appears that you
are), you would do something like this:

$sql = mysql_query(SELECT * FROM table ORDER BY rand());

if(mysql_error())
echo SQL not executed successfully.;
else
print SQL executed successfully.;


Josh Hoover
KnowledgeStorm, Inc.
[EMAIL PROTECTED]

Searching for a new IT solution for your company? Need to improve your
product marketing? 
Visit KnowledgeStorm at www.knowledgestorm.com to learn how we can simplify
the process for you.
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 This works:
 if ($connection = mysql_connect(host,username,password)) {
 print Successful connection:
 }
 else {
 print No connection;
 }
 
 But this won't work:
 
 if ($sql = mysql_query(SELECT * FROM table ORDER BY rand())) {
 print SQL executed successfully.;
 }
 else {
 print SQL not executed successfully.;
 }
 
 Can anyone tell me how I can tell if the SQL executed 
 successfully?  Is
 there any method besides OR DIE? 

Re: [PHP] sql query successful

[Tyler Longren]

What about when DELETING from a table???  It always returns true.
Example...the highest ID in this table is 10:

?
if ($connection = mysql_connect(localhost,mysql,mysql)) {
print Connection established;
$db = mysql_select_db(aanr, $connection);
if ($sql = mysql_query(DELETE FROM bullitens WHERE id='1212')) {
print Successful;
}
else {
print Not successful.;
}
}
else {
print Connection NOT established.;
}
?

We try to delete the bulliten with id of 1212, but there is not bulliten
with that ID, and it says Successful.

I know I could use mysql_affected_rows(), but why doesn't this work???

Tyler

- Original Message -
From: Mark Roedel [EMAIL PROTECTED]
To: Tyler Longren [EMAIL PROTECTED]; php-general
[EMAIL PROTECTED]
Sent: Wednesday, July 18, 2001 1:30 PM
Subject: RE: [PHP] sql query successful


 -Original Message-
 From: Tyler Longren [mailto:[EMAIL PROTECTED]]
 Sent: Wednesday, July 18, 2001 1:25 PM
 To: php-general
 Subject: [PHP] sql query successful


 I've been writing database enabled site for quite a while
 now.  One thing I have never figured out it how to determine
 if a sql query is successful.

 This works:
 if ($connection = mysql_connect(host,username,password)) {
 print Successful connection:
 }
 else {
 print No connection;
 }

 But this won't work:

 if ($sql = mysql_query(SELECT * FROM table ORDER BY rand())) {
 print SQL executed successfully.;
 }
 else {
 print SQL not executed successfully.;
 }

In what way doesn't this work?

The above code should tell you that the query was properly formed and
error-free, and was cheerfully accepted and processed by the database
server.  (You don't get much more successful than that...)

If what you're really looking for is whether there were any rows
returned by the query, then you'll want to look into the
mysql_num_rows() function.


---
Mark Roedel ([EMAIL PROTECTED])  ||  There cannot be a crisis next week.
Systems Programmer / WebMaster  ||   My schedule is already full.
 LeTourneau University  ||-- Henry Kissinger



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Re: [PHP] sql query successful

[Christopher Ostmo]

Tyler Longren pressed the little lettered thingies in this order...

 Hello everyone,
 
 I've been writing database enabled site for quite a while now.  One thing I
 have never figured out it how to determine if a sql query is successful.
 
 This works:
 if ($connection = mysql_connect(host,username,password)) {
 print Successful connection:
 }
 else {
 print No connection;
 }
 
 But this won't work:
 
 if ($sql = mysql_query(SELECT * FROM table ORDER BY rand())) {
 print SQL executed successfully.;
 }
 else {
 print SQL not executed successfully.;
 }
 
 Can anyone tell me how I can tell if the SQL executed successfully?  Is
 there any method besides OR DIE?
 

What's wrong with or die(... ? If you get no error, the query was 
successful.  If you take your $sql = out it *should* work.  mysql_query 
returns TRUE or FALSE depending on whether or not the query 
succeeded. This isn't tested, but it should work:
if (mysql_query(SELECT * FROM table ORDER BY rand())) {
echo Success!;
} else {
echo Failure!;
}

Your statement above is checking to see if the fact that $sql is equal to 
mysql_query(SELECT * FROM table ORDER BY rand()) is TRUE, but 
you're using an assignment operator (=) and not a comparison operator 
(==), so it should always return FALSE. (Can you use an assignment 
operator in an if() statement?)


Christopher Ostmo
a.k.a. [EMAIL PROTECTED]
AppIdeas.com
Innovative Application Ideas
Meeting cutting edge dynamic
web site needs since the 
dawn of Internet time (1995)

Business Applications:
http://www.AppIdeas.com/

Open Source Applications:
http://open.AppIdeas.com/

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RE: [PHP] sql query successful

[Mark Roedel]

 -Original Message-
 From: Christopher Ostmo [mailto:[EMAIL PROTECTED]]
 Sent: Wednesday, July 18, 2001 2:43 PM
 To: [EMAIL PROTECTED]
 Subject: Re: [PHP] sql query successful
 
 
 Your statement above is checking to see if the fact that $sql 
 is equal to mysql_query(SELECT * FROM table ORDER BY rand())
 is TRUE, but you're using an assignment operator (=) and not a
 comparison operator (==), so it should always return FALSE. (Can
 you use an assignment operator in an if() statement?)

Actually, you can.  (See
http://www.php.net/manual/en/language.operators.assignment.php)

An assignment operation will return the value that was assigned.

Thus, if we have

if ($sql = mysql_query($query_string))

and the mysql_query call returns a non-false value, the entire
expression will evaluate to true.


---
Mark Roedel   | The most overlooked advantage to owning a
Systems Programmer|  computer is that if they foul up there's no
LeTourneau University |  law against whacking them around a little.
Longview, Texas, USA  |  -- Owen Porterfield 

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Re: [PHP] sql query successful

[Christopher Ostmo]

Tyler Longren pressed the little lettered thingies in this order...

 What about when DELETING from a table???  It always returns true.
 Example...the highest ID in this table is 10:
 
 ?
 if ($connection = mysql_connect(localhost,mysql,mysql)) {
 print Connection established;
 $db = mysql_select_db(aanr, $connection);
 if ($sql = mysql_query(DELETE FROM bullitens WHERE id='1212')) {
 print Successful;
 }
 else {
 print Not successful.;
 }
 }
 else {
 print Connection NOT established.;
 }
 ?
 
 We try to delete the bulliten with id of 1212, but there is not bulliten
 with that ID, and it says Successful.
 
 I know I could use mysql_affected_rows(), but why doesn't this work???
 

mysql_query() is not intended to be used as a means by which you can 
check the number of rows that are affected.  If it returned FALSE severy 
time your query was empty, you would have to rewrite all of your of code 
to eliminate errors.  It only checks for the validity of your query.

To ask why this doesn't work would be the same thing as asking why 
you can type this query from the command-line mysql client and the 
query succeeds without an error. It succeeds and says 0 rows.

It's a valid query with zero results.  A FALSE return from a programming 
function indicates an error condition, not the lack of results.

Christopher Ostmo
a.k.a. [EMAIL PROTECTED]
AppIdeas.com
Innovative Application Ideas
Meeting cutting edge dynamic
web site needs since the 
dawn of Internet time (1995)

For a good time,
http://www.AppIdeas.com/

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RE: [PHP] sql query successful

[Christopher Ostmo]

Mark Roedel pressed the little lettered thingies in this order...

  -Original Message-
  From: Christopher Ostmo [mailto:[EMAIL PROTECTED]]
  Sent: Wednesday, July 18, 2001 2:43 PM
  To: [EMAIL PROTECTED]
  Subject: Re: [PHP] sql query successful
  
  
  Your statement above is checking to see if the fact that $sql 
  is equal to mysql_query(SELECT * FROM table ORDER BY rand())
  is TRUE, but you're using an assignment operator (=) and not a
  comparison operator (==), so it should always return FALSE. (Can
  you use an assignment operator in an if() statement?)
 
 Actually, you can.  (See
 http://www.php.net/manual/en/language.operators.assignment.php)
 
 An assignment operation will return the value that was assigned.
 
 Thus, if we have
 
   if ($sql = mysql_query($query_string))
 
 and the mysql_query call returns a non-false value, the entire
 expression will evaluate to true.
 

Thank you.  I've never tried to assign within an if() clause.

You learn 13 or 14 new things every day...

Christopher Ostmo
a.k.a. [EMAIL PROTECTED]
AppIdeas.com
Innovative Application Ideas
Meeting cutting edge dynamic
web site needs since the 
dawn of Internet time (1995)

For a good time,
http://www.AppIdeas.com/

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PHP General Mailing List (http://www.php.net/)
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
To contact the list administrators, e-mail: [EMAIL PROTECTED]

RE: [PHP] sql query successful

[Mark Roedel]

 -Original Message-
 From: Tyler Longren [mailto:[EMAIL PROTECTED]]
 Sent: Wednesday, July 18, 2001 1:36 PM
 To: Mark Roedel; php-general
 Subject: Re: [PHP] sql query successful
 
 
 What about when DELETING from a table???  It always returns true.
 Example...the highest ID in this table is 10:
 
 ?
 if ($connection = mysql_connect(localhost,mysql,mysql)) {
 print Connection established;
 $db = mysql_select_db(aanr, $connection);
 if ($sql = mysql_query(DELETE FROM bullitens WHERE 
 id='1212')) {
 print Successful;
 }
 else {
 print Not successful.;
 }
 }
 else {
 print Connection NOT established.;
 }
 ?
 
 We try to delete the bulliten with id of 1212, but there is 
 not bulliten with that ID, and it says Successful.

 I know I could use mysql_affected_rows(), but why doesn't this work???

Because the query itself is still valid.  No syntax errors, no
connection errors, etc.  The fact that there wasn't any data that needed
to be deleted doesn't affect the validity of the query; just the results
of it.

Basically, what it boils down to is that There wasn't anything for me
to do is not an error.  It's a perfectly valid result.  :)


---
Mark Roedel ([EMAIL PROTECTED])  ||  There cannot be a crisis next week.
Systems Programmer / WebMaster  ||   My schedule is already full.
 LeTourneau University  ||-- Henry Kissinger


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