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What is the most common way to access data in the world today? If pressed for this answer, I would have to say it is Microsoft DAO (a.k.a. Data Access Object) whether it be with a VB, Access or VC++ front-end or with an Access or enterprise-level back-end. The greatest single group of application programmers use DAO, period. This first stab at providing the most important parts of DAO (i.e. those that are use about 90% of the time) is my hope that many ASP programmers, sickened by Microsoft's insistance that web-based programming be done with the cumbersome, twitchy, and many times over-complicated ADO (ActiveX Data Object) may turn to PHP and MySQL without having to relearn a different data access methodology. There are some important things missing in this first release. Recordset objects don't have the old "edit/update" functionality, and in this first release don't even have a findfirst/findnext method (but it is coming). But even with all the missing pieces, this release allows you to do everything you need to: query the database, execute SQL commands, traverse recordsets, object-based approaches. AND its available by including just one small file at the top of every PHP script you write. Email me with your thoughts people! I'll get to it faster if there is a need out <? // ************ set these constants to automatically connect to the local MySQL listener $gcon_mysqlhost = "localhost"; $gcon_mysqluid = "username"; $gcon_mysqlpwd = "password"; // *************************************************************************** *********** function opendatabase($dbname) { return new dao_database($dbname); } class dao_database { //*** public properties*** //DAO properties var $databasename; // (get only) //MySQL Back-Door Properties (use these only when absolutely necessary, or not at all!) var $connection_handle; // (get only) var $databased_select_handle; // (get only) //*** private *** // (note: its my own convention that private varaibles are given the "l_" prefix, for "local") var $l_databasename; var $l_ch; var $l_dsh; //*** constructor **** function dao_database($dbname) { //make available the globals for mysql connectivity within this class (PHP does this funny- like) global $gcon_mysqlhost, $gcon_mysqluid, $gcon_mysqlpwd; //DAO users: don't use this method directly, use the more familiar opendatabase() function $this->l_ch=mysql_connect($gcon_mysqlhost, $gcon_mysqluid, $gcon_mysqlpwd); $this->l_dsh = mysql_select_db($dbname,$this->l_ch); //error check if ((intval($this->l_ch)==0)||(intval($this->$l_dsh)==0)) return false; $this->databasename=$dbname; $this->l_databasename=$dbname; return true; } function openrecordset($sql) { return new dao_recordset($sql,$this->l_ch); } function execute($sql) { mysql_query($sql,$this->l_ch); return true; } function close() { //note: this does not remove the database object from PHP, nor does it close the MySQL connection (as mysql_connect() re-uses connection handles and we may inadvertently close another database object's connection) //what does it do then? Right now nothing, but in the near future it will close access to the object's methods, returning an error. return true; } } class dao_recordset{ //*** public *** //DAO properties var $eof; //(get only) var $nomatch; //(get only) var $fields_count; //(get only) var $recordcount; //(get only) //*** private *** var $l_res; var $l_sql; var $l_numrows; var $l_currownum; //this is the result set's current internal seek index var $l_currow; //this is the row array returned by mysql_fetch_row containing the current rows literal data; //*** private helper functions *** (DO NOT CALL PUBLICALLY UNDER ANY CIRCUMSTANCES!) function translate_fieldname_to_ordinal($fn) { for ($a=0;$a<$this->fields_count;$a++) { //make it fieldnames case insensitive (important DAO feature!) $fn=strtolower($fn); if (strtolower($this->fields_name($a))==$fn) return $a; } return -1; } //*** constructor *** function dao_recordset($sql,$ch) { $this->l_res=mysql_query($sql,$ch); //set the internal vars to correct values $this->l_sql = $sql; $this->l_numrows = intval(mysql_num_rows($this->l_res)); $this->l_currow = 0; $this->fields_count=mysql_num_fields($this->l_res); //remember that it is possible to have a recordset WITH ZERO ROWS! if ($this->l_numrows==0) { $this->eof=true; $this->l_currow=NULL; } else { $this->eof=false; $this->l_currow=mysql_fetch_row($this->l_res); } //set the DAO property "Recordcount" $this->recordcount=intval($this->l_numrows); return true; } //*** methods *** function value($fn) { //Pain-in-the-butt: Microsoft's object model allows definition of a "default" property // that allows the following usage (in VB): // // r$ = recordset1("userid") // // but in PHP (because of language limitations), you must use the "value" method to // return the data in a field, like this (in PHP): // // $r=recordset1->value("userid"); //IMPORTANT: Technically, DAO formally perpetuates the field type to the variable type, but since // PHP does NOT support variable typing (neither does MySQL for that matter) the variable // will always be intepreted as a STRING (i.e. a CHAR or a VARCHAR for you DB junkies out there!) //note: DAO allows access via field name or field ordinal, see what it is if (intval($fn)==0) $fn=$this->translate_fieldname_to_ordinal(strval($fn)); return strval($this->l_currow[intval($fn)]); } function movenext() { if ($this->eof!=true) { $this->l_currow=mysql_fetch_row($this->l_res); if ($this->l_currow==false) { $this->eof=true; $this->l_currownum=-1; } else { $this->l_currownum++; } } } function movefirst() { mysql_data_seek($l_res,0); $l_currownum=0; $l_currow=mysql_fetch_row($l_res); if ($l_numrows>0) $eof=false; } function movelast() { mysql_data_seek($l_res,$l_numrows); $l_currownum=$l_numrows; $l_currow=mysql_fetch_row($l_res); $eof=true; } function moveprevious() { if ($l_currownum==0) { $bof=true; return false; } mysql_data_seek($res,$l_currownum-1); $l_currownum--; $l_currow=mysql_fetch_row($l_res); return true; } /* // findfirst and findnext are NOT IMPLEMENTED IN THIS VERSION OF DAO.PHP3 function find($wc) { //let's see if you can figure out what I am doing here! //form a modified version of the record set's source SQL $s=strtolower($this->l_sql); $insert_pos=strpos(1,$s,"where"); if (($insert_pos)==false) { //there is no where clause in the original SQL, place one after " ...FROM tablename..." $insert_pos=strpos(1,$s," from "); $sc=0; for ($a=$insert_pos;($a<strlen($s))&&($sc<4);$a++) { $c=substr($s,$a,1); if ($c==" ") $sc++; } $insert_pos=$a; if ($insert_pos==strlen($s)) $ms="$s where $wc"; else $ms=substr($s,0,$insert_pos)." where $wc ".substr($s,$insert_pos+1); } else { $ms=substr($s,0,$insert_pos+4)." and ($wc) ".substr($s,$insert_pos+5); } //debug echo("Original: $this->l_sql<p>Modified: $ms<p>\n"); } // findfirst($whereclause); // findnext($whereclause); */ function fields_name($fo) { return mysql_field_name($this->l_res,intval($fo)); } function fields_type($fo) { $ft=mysql_field_type($this->l_res, intval($fo)); //we really should translate this type value from MySQL native value to //one recognizable to DAO users (i.e. convert VARCHAR codes to "char" codes, and TEXT/BLOB codes to "Memo" codes return $ft; } function close() { mysql_free_result($this->l_res); $this->l_sql=""; $this->eof=true; $this->bof=true; $this->l_currow=NULL; $this->l_currownum=0; $this->l_numrows=0; $this->recordcount=0; $this->nomatch=true; } } ?> Example : ======== <html> <? //remember to set up the global constants in dao.php3 before using... include("dao.php3"); $db=opendatabase("yourdatabasename"); $rs1=$db->openrecordset("select * from users"); echo($rs1->recordcount." records were returned.\n"); if ($rs1->recordcount>0) { echo("<table border=1 cellpadding=3>\n"); while ($rs1->eof==false) { $username=$rs1->value("username"); $password=$rs1->value("password"); echo("<tr><td><center>$username</td><td><center>$password</td></tr>\n"); $rs1->movenext(); } echo("</table>\n"); } $rs->close(); ?> </html> | |||||
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