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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: Lynna Landstreet <lynna(at)spidersilk(dot)net>, pgsql-php(at)postgresql(dot)org
Subject: Re: display query results
Date: 2008-07-30 21:02:46
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-php
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() [ 
>> <http://biggie/k2/>]: 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
>       $db = pg_connect("host=localhost port=5432 dbname=med user=med
> password=0tscc71");
>       // Note: according to 
> a resource 
> always evaluates to true,
>       // therefore !$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 
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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