Re: display query results

From: PJ <af(dot)gourmet(at)videotron(dot)ca>
To: Andy Shellam <andy(dot)shellam-lists(at)mailnetwork(dot)co(dot)uk>
Cc: pgsql-php(at)postgresql(dot)org
Subject: Re: display query results
Date: 2008-07-31 13:55:05
Message-ID: 4891C439.6000106@videotron.ca
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I knew it was too good to be true.
Now I am trying to verify the padding on "Alcohol" and in so doing tried
to invoke phpPgAdmin... and you gussed it, I tried to follow all hte
INSTALL instructions and http://localhost/phppgadmin just gives "cannot
find on this server"
On to of it, the same script I ran yesterday now give me "Fatal error"
Call to undefined function pg_connect() on line 10. Worked fine yesterday.
Wonder what it is that I screwed up?

Andy Shellam wrote:
> Haha, no worries, I've had the same issue before.
> It's almost certain that the text in your column does not exactly
> match "Alcohol" for one of a few reasons, e.g.
>
> "Alcohol " (right-padding)
> " Alcohol" (left-padding)
> " Alcohol " (padded both sides)
>
> will not match = 'Alcohol' in the query.
> Try trimming the data in that field - from PgAdmin or some other query
> tool, run something like:
>
> |UPDATE glossary_item SET "name" = |trim(both ' ' from "name")
>
> WARNING: I've not tried the above query so make sure you have a backup
> of your data before you run it ;-)
> Then try changing your PHP query back to = again.
>
> Andy
>
> PJ wrote:
>> I want to thank everyone for their contribution. As usual, the
>> solution turns out to be simple. Remeber the KISS principle.
>> see the note within the text: the LIKE condition did it. But I will
>> have more questions as I grope further in the dark. :))
>>
>> Andy Shellam wrote:
>>> Just shooting in the dark here, but I'm thinking there might be some
>>> extra spaces around the column values. For some reason PostgreSQL
>>> is not returning any rows for that query, which is where the root of
>>> your problem lies.
>>>
>>> Do you have PgAdmin? If so try the exact same query against the
>>> same database and server.
>>> Also try changing your query as follows:
>>>
>>> SELECT description FROM glossary_item WHERE name LIKE '%Alcohol%'
>> Great aim for shooting in the dark. :)) That was it.
>> Now, could someone explain why I need the LIKE statement?
>> I will try to check the documentation...
>>>
>>> and see what you get.
>>>
>>> Regards,
>>>
>>> Andy
>>>
>>>
>>> PJ wrote:
>>>> Annotated within text below:
>>>>
>>>> Andy Shellam wrote:
>>>>> PJ wrote:
>>>>>> Lynna Landstreet wrote:
>>>>>> Well, it does explain things a little. Unfortunately, I have
>>>>>> tried about everything imaginable before posting except the right
>>>>>> thing.
>>>>>> I can not visualize what it is that my query is returning. Here
>>>>>> is what the code is:
>>>>>>
>>>>>> Whatever I enter as values for pg_fetch_result, the screen
>>>>>> output is :
>>>>>>
>>>>>> resource(3) or type (pgsql result)
>>>>>> *Warning*: pg_fetch_result() [function.pg-fetch-result
>>>>>> <http://biggie/k2/function.pg-fetch-result>]: Unable to jump to
>>>>>> row 1 on PostgreSQL result index 3 in
>>>>>> */usr/local/www/apache22/data/k2/test1_db.php* on line *29*
>>>>>
>>>>> This suggests that there is no row 1 in your result-set. I
>>>>> believe it is zero-based, so try fetching row 0 if your query only
>>>>> returns 1 row.
>>>> Been there, done that. No change.
>>>>>
>>>>>
>>>>>> I don't understand what $resuts is returning - if it is an entire
>>>>>> row, the one that the field is in that I am looking for, then why
>>>>>> do I not get a printout of the text that is in that field? The
>>>>>> row in the table is the second row and the field I am trying to
>>>>>> retrieve is the 4th field.
>>>>> $results as explained previously is just a pointer to a
>>>>> recordset. This analogy isn't brilliant, but think of your
>>>>> database table as a book. Each row on a page within that book is
>>>>> a record, and the words in that row are the data in the table's
>>>>> columns.
>>>>>
>>>>> When you run a query, think of yourself looking at the book's
>>>>> index for a given word. The index will tell you the pages that
>>>>> word is on. That's your $results - simply a pointer to your data.
>>>>>
>>>>> You then need to turn to that page in the book (pg_fetch_*
>>>>> functions) to start examining the lines for the word you want.
>>>>> Once you've got your line, you can find the word (column/data,
>>>>> from your array) you're looking for.
>>>>>
>>>>> Now turn that into PHP and SQL. You run your query (looking in
>>>>> the book's index) and the PostgreSQL driver will save the results
>>>>> into a block of memory in your server's RAM, returning a resource
>>>>> identifier. This is literally just saying "resource #3 is located
>>>>> at this location in the computer's memory." When you look up a
>>>>> record from that result-set, PHP then knows where to look for the
>>>>> data.
>>>>>
>>>>> I never really use the "or die" syntax, I tend to explicitly check
>>>>> the return values of the functions. Try this:
>>>>>
>>>>> <?php
>>>>> $db = pg_connect("host=localhost port=5432 dbname=med user=med
>>>>> password=0tscc71");
>>>>>
>>>>> // Note: according to
>>>>> http://uk2.php.net/manual/en/language.types.boolean.php a resource
>>>>> always evaluates to true,
>>>>> // therefore !$db may not evaluate to false when connection
>>>>> fails.
>>>>> if ($db === false)
>>>>> {
>>>>> die("Could not open connection to database server");
>>>>> }
>>>>>
>>>>> // generate and execute a query
>>>>> $query = "SELECT description FROM glossary_item WHERE
>>>>> name='Alcohol'";
>>>>> $results = pg_query($db, $query);
>>>>> var_dump ($results);
>>>>>
>>>>> if ($results === false)
>>>>> {
>>>>> die("SQL query failed: " . pg_last_error($db));
>>>>> }
>>>>> else if (pg_num_rows($results) == 0)
>>>>> {
>>>>> // Only do this if you were expecting at least 1 row back
>>>>> die("SQL query returned no rows");
>>>>> }
>>>>>
>>>>> $results_formatted = pg_fetch_all($results);
>>>>> echo "<pre>"; // need this to show output better in a HTML page
>>>>> var_dump($results_formatted);
>>>>> echo "</pre>"; // need this to show output better in a HTML
>>>>> page
>>>>>
>>>>> /*
>>>>> $results_formatted will then be set out like follows:
>>>>>
>>>>> $results_formatted[row_index][column_name] = column_value
>>>>> */
>>>>> pg_close($db);
>>>>> ?>
>>>> Tried your coding - returns: resource(3) of type (pgsql result) SQL
>>>> query returned no rows
>>>> The row is there... isn't that what were asking for?
>>>> To go by the book, I even changed the description to * as noted
>>>> before below.
>>>> Something is rotten in Denmark.
>>>> This is getting ridiculous - I have followed the instructions as
>>>> specified in the Postgresql documentation and examples - and it
>>>> just doesn't work.
>>>>
>>>> The db is like this..
>>>> int4 ||int4 || varchar(32)|| text
>>>> _item_id || glossary_id || name || description _
>>>> 2 || 1 || Alcohol || One of thetwo
>>>> major.... blah...blah.. blah
>>>>>> Am I querying correctly? The table is "glossary_item", the row I
>>>>>> want is the one that is unique in containing the word "Alcohol"
>>>>>> in the column "name"
>>>>>>
>>>>>> I changed: $query = "SELECT * FROM glossary_item WHERE name=
>>>>>> 'Alcohol'";
>>>>>> same result
>>>>>>
>>>>>> Picture me tearing out my hair...
>>>>>>
>>>>>
>>>>> Regards,
>>>>>
>>>>> Andy
>>>>>
>>>>
>>>>
>>>
>>
>>
>

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