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All For One, And One For All - PHP

You've already seen how PHP can be used to interface with Java components and JavaBeans. But here's something you didn't know - PHP can (shock shock! horror horror!) even be used to interface with Microsoft COM objects on the Windows platform. Will this be a happy marriage? Read on to find out.

TABLE OF CONTENTS:
  1. PHP and COM
  2. Striving To Excel
  3. The Number Game
  4. Export Potential
  5. Keeping It Simple
  6. Access-ing The Web
  7. All For One, And One For All
  8. New Coins For Old
  9. Link Zone
By: Harish Kamath, (c) Melonfire
Rating: starstarstarstarstar / 15
April 23, 2002

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What I need now is a script that lets me view records, add records, edit records and delete records. For convenience, I'm going to put all these functions into a single script, with a series of "if" tests to determine which function to activate every time the script is executed.

Here's the broad outline of what the script will look like:

<?php // start storing the content in a buffer ob_start(); // page header // set some defaults if(!isset($nextopid) && !isset($previousopid)) { $nextopid = "list"; $previousopid = ""; } // make a choice as to what function is needed if($nextopid == "list") { // code to list all records } else if($nextopid == "add" || ($nextopid == "edit" && isset($id))) { // code to display HTML form to add or modify records } else if($nextopid == "add_process") { // code to add new record } else if($nextopid == "edit_process") { // code to update selected record } else if($nextopid == "delete") { // code to delete selected record } // page footer // display buffer contents ob_end_flush(); ?>
As you can see from the code above, there are just two variables used to control the entire script (they're initialized with default values at the top of the script). The more important of the two is the $nextopid variable, which tells the script which operation to perform; it can contain any one of the following values:

"list" - list all records in the table;

"add" - display a form for adding new records;

"edit" - display a form for editing an existing record (must be passed the ID of the record as well);

"add_process" - process the form data and INSERT the record into the table;

"edit_process" - process the form data and UPDATE the record in the table;

"delete" - DELETE the selected record from the table.

Let's look at the code for each of these in detail.

<?php // code to list all records if($nextopid == "list") { // check to see what the previous operation was // if null, do nothing // if value exists, display an appropriate message // to indicate the results of that operation if(isset($previousopid) && $previousopid != "") { switch ($previousopid) { case "add_process": echo "<h3>Record successfully added</h3>"; break; case "edit_process": echo "<h3>Record successfully updated</h3>"; break; case "delete": echo "<h3>Record successfully deleted</h3>"; break; default: echo "&nbsp;"; } } ?> <h4 align="left">Coin Listing</h4> <table border="2" cellpadding="5" cellspacing="1" width="90%"> <tr> <th width="5%" align="right">#</th> <th width="20%" align="left">Name</th> <th width="20%" align="left">Country</th> <th width="15%" align="right">Weight <br>(in gms.)</th> <th width="5%" align="right" >Year</th> <th width="20%" align="left">Remarks</th> <th width="5%" align="right" >&nbsp;</th> <th width="5%" align="right" >&nbsp;</th> </tr> <?php // open up a connection to the database $DB_Conn = new COM("ADODB.Connection") or die("Cannot start ADO"); $DB_Conn->Open("phpcom"); // execute a query $RS_Record = $DB_Conn->Execute("SELECT * FROM coins"); // iterate through the recordset while (!$RS_Record->EOF) { // get the field data into variables $id = $RS_Record->Fields('id'); $name = $RS_Record->Fields('name'); $country = $RS_Record->Fields('country'); $weight = $RS_Record->Fields('weight'); $year = $RS_Record->Fields('year'); $remarks = $RS_Record->Fields('remarks'); ?> <tr> <td width="5%" align="right"><?php echo $id->value; ?></td> <td width="20%" align="left"><?php echo $name->value; ?></td> <td width="20%" align="left"><?php echo $country->value; ?></td> <td width="5%" align="right"><?php echo $weight->value; ?></td> <td width="10%" align="right"><?php echo $year->value; ?></td> <td width="35%" align="left"><?php echo $remarks->value; ?></td> <td width="5%" align="right" ><a href="<?php echo $PHP_SELF."?nextopid=edit&previousopid=list&id=".$id->value;?>">Edit</a> </td> <td width="5%" align="right" ><a href="<?php echo $PHP_SELF."?nextopid=delete&previousopid=list&id=".$id->value;?>">Delete </a> </td> </tr> <?php // go to the next record $RS_Record->MoveNext(); } ?> <tr> <td colspan="8" align="right"><a href="<?php echo $PHP_SELF."?nextopid=add&previousopid=list";?>">Add New</a></td> </tr> </table> <?php // clean up $RS_Record->Close(); $DB_Conn->Close(); $RS_Record = null; $DB_Conn = null; // end of "list" block } ?>
Over here, I've used COM to create an instance of the ADODB.Connection class - this allows me to open a connection to the DSN created on the previous page. Next, I've executed a query to SELECT all the records present in the table and store them in a record set. Then I've iterated through the record set and displayed all the fields on a Web page. Note my usage of the Fields() method to do this.

Here's what the output looks like:



Next up, adding and editing coins. Since the form displayed for both these operations is similar, I can combine the two operations into a single block. If the operation is an "add" operation, the form will be displayed with empty fields; if it is an "edit" operation, the record ID passed to the script will be used to query the table for the record and pre-fill the form fields with data.

<?php if($nextopid == "add" || ($nextopid == "edit" && isset($id))) { // code to display HTML form to add or modify records ?> <h4 align="left"><?php echo ucfirst($nextopid)." Coin"; ?></h4> <?php if ($nextopid == "edit" && isset($id)){ // if this is an edit operation // use the ID to retrieve the record from the table $DB_Conn = new COM("ADODB.Connection") or die("Cannot start ADO"); $DB_Conn->Open("phpcom"); // run query $query = "SELECT name, country, weight, year, remarks FROM coins where id = $id"; $RS_Record = $DB_Conn->Execute($query); // iterate through recordset while (!$RS_Record->EOF) { $name = $RS_Record->Fields('name'); $name = $name->value; $country = $RS_Record->Fields('country'); $country = $country->value; $weight = $RS_Record->Fields('weight'); $weight = $weight->value; $year = $RS_Record->Fields('year'); $year = $year->value; $remarks = $RS_Record->Fields('remarks'); $remarks = $remarks->value; $RS_Record->MoveNext(); } // clean up $RS_Record->Close(); $DB_Conn->Close(); $RS_Record = null; $DB_Conn = null; } ?> <form action="<?php echo $PHP_SELF;?>" method="post" > <?php if(isset($id)) {?><input type="hidden" name="id" value="<?php echo $id;?>"><?php } ?> <input type="hidden" name="previousopid" value="<?php echo $nextopid;?>"> <input type="hidden" name="nextopid" value="<?php echo $nextopid;?>_process"> <table border="2" cellpadding="10" cellspacing="1" width="90%"> <tr> <th align="left">Coin characteristics</th> <th align="left"><?php echo ucfirst($nextopid); ?> Value</th> </tr> <tr> <td align="right">Name</td> <td align="left"><input type="text" name="name" size="30" maxlength="30" value="<?php if(isset($name)) echo trim($name);?>"></td> </tr> <tr> <td align="right">Country</td> <td align="left"><input type="text" name="country" size="30" maxlength="30" value="<?php if(isset($country)) echo trim($country);?>"></td> </tr> <tr> <td align="right">Weight (in gms)</td> <td align="left"><input type="text" name="weight" size="10" maxlength="10" value="<?php if(isset($weight)) echo trim($weight);?>"></td> </tr> <tr> <td align="right">Year</td> <td align="left"><input type="text" name="year" size="10" maxlength="10" value="<?php if(isset($year)) echo trim($year);?>"></td> </tr> <tr> <td align="right">Remarks</td> <td align="left"><textarea name="remarks" cols="40" rows="4"><?php if(isset($remarks)) echo trim($remarks);?></textarea></td> </tr> <tr> <td colspan="2" align="right"><input type="submit" value="<?php echo ucfirst($nextopid);?> Coin" >&nbsp;&nbsp;<input type="reset" value="Clear above form"></td> </tr> <tr> <td colspan="2" align="right"><a href="<?php echo $PHP_SELF."?nextopid=list"; ?>">Back to listing</a></td> </tr> </table> </form> <? // end of "add" or "edit" condition } ?>
Once I know that the user is editing a record, it's trivial to create another ADODB connection to the database to fetch the details of the entry and display a pre-filled form. If, on the other hand, the user is adding a record, I can skip the entire process of fetching the record from the database and just display a blank form.

Here's what the two forms look like:





Note the values of $nextopid in both cases above - for an "add" operation, $nextopid is set to "add_process", and for an "edit" operation, it's set to "edit_process". Let's take a look at those next.

 
 
>>> More PHP Articles          >>> More By Harish Kamath, (c) Melonfire
 

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