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13. Appendix A Database Wrapper Example

Submitted by: Barton Greg [email protected] To get this file, in the web-browser, save this file as 'Text' type as pgsql.lib

This  is  a  database   wrapper  for  PostgreSQL,  but   
can  be  simply  modified  for  any  other   database  type.


<?php

if ($dbObjDefined  !=  1)
{
        $dbObjDefined  =  1;

        // Wrapper  class  for  database  calls
        class  dbObj
        {
                // Connection  handle  to  database
                var  $conn;

                // Default  connection  parameters
                var  $host  =  "YourSite.com";
                var  $user  =  "johndoe";
                var  $password  =  "pwd";
                var  $port  =  "5432";
                var  $dbname  =  "MyDB";

                // Open  initial  connection.  $params  is  
                // an  associative  array  holding
                // parameters  to  the  pg_Connect  function.
                function  init($params)
                {
                        if(isset($parame[host]))
                                $host  =  $parame[host];
                        else
                                $host  =  $this->host;

                        if(isset($parame[user]))
                                $user  =  $parame[user];
                        else
                                $user  =  $this->user;

                        if(isset($parame[password]))
                                $password  =  $parame[password];
                        else
                                $password  =  $this->password;

                        if(isset($parame[port]))
                                $port  =  $parame[port];
                        else
                                $port  =  $this->port;

                        if(isset($parame[dbname]))
                                $dbname  =  $parame[dbname];
                        else
                                $dbname  =  $this->dbname;

                        $this->conn  =  pg_Connect ( "  host=$host  user=$user  password=$password  port=$port  dbname=$dbname ");
                }

                // Send  SQL  to  database  connection.
                // Return  recordset  object  on  success.
                // Return  0  on  failure.
                function  exec($SQL)
                {
                        $this->resultset  =  pg_Exec($this->conn,  $SQL);

                        if  ($this->resultset)  
                        {
                                $recset  =  new  recordset;
                                $recset->init($this->resultset);
                                return  $recset;
                        }
                        else  
                        {
                                return  0;
                        }
                }

                function valid()
                {
                        return $this->resultset;
                }

                // Close  connection  to  database
                function  free()
                {
                        pg_close($this->conn);
                }
        };

        /*
        ** This  is  a  simple  recordset  class  which  can  be
        ** traversed  using  next(),  prev(),  and  current()  methods.
        ** It  is  initialized  from  a  resultset  returned  from  the
        ** function  "pg_Exec"  or  can  be  generated  by  a  call  to  the
        ** exec  method  from  the  dbObj class given above.
        ** Below "Tuples" means rows.
        */
        class  recordset
        {
                var  $resultset;
                var  $index;
                var  $numFields;
                var  $numTuples;

                function  init($newResultset)
                {
                        $this->resultset  =  $newResultset;
                        $this->index  =  0;
                        $this->numFields  =  pg_NumFields($this->resultset);
                        $this->numTuples  =  pg_NumRows($this->resultset);
                }

                // Used in display() below
                function valid()
                {
                        return $this->resultset;
                }

                // Get  a  value  by  row  number  and  either  
                // column  name  or  column  number
                function  getVal($row,  $col)
                {
                        return  pg_Result($this->resultset,  $row,  $col);
                }

                // Return  an  array  of  field  names
                function  getFields()
                {
                        for ($i=0;  $i < $this->numFields;  $i++)
                                $retArray[] = pg_FieldName($this->resultset,  $i);
                        return  $retArray;
                }

                // Get  number  of  columns  in  resultset
                function  getNumFields()
                {
                        return  $this->numFields;
                }

                // Get  a  tuple  (associative  array  of  
                // column  values)  by  row  number
                function  getTupleDirect($row)
                {
                        for ($i=0;  $i < $this->numFields;  $i++)
                        {
                                $retArray[pg_FieldName($this->resultset,  $i)]  = 
                                        pg_Result($this->resultset,  $row,  $i);
                        }
                        return  $retArray;
                }

                // Get  an  array  filled  with  all  values  in  a  column
                // (using  either  column  name  or  column  number)
                function  getColumn($col)
                {
                        for ($i=0; $i < $this->numTuples; $i++)
                                $retArray[]  =  pg_Result($this->resultset,  $i,  $col);
                        return  $retArray;
                }

                // Return  the  number  of  records  in  the  recordset
                function  getNumTuples()
                {
                        return  $this->numTuples;
                }

                // Get  tuple  pointed  to  by  the  current  index
                function  getTuple()
                {
                        if ($this->index >= 0  &&  $this->index  <  $this->numTuples)
                                return  $this->getTupleDirect($this->index);
                        else
                                return  0;
                }

                function valueof($col)
                {
                        if ($col < $this->numFields)
                        {
                                return pg_Result($this->resultset,  $this->index,  $col);
                        }
                        else
                        {
                                return "";
                        }
                }

                // Reached last row - end of rows ? Used in display() below
                function eof()
                {
                        return $this->index == $this->numTuples;
                }

                // Return  1  if  index  is  within  bounds  of  the  recordset
                function  current()
                {
                        if ($this->index >= 0  &&  $this->index  <  $this->numTuples)
                                return  1;
                        else
                                return  0;
                }

                // Increment  index. Used in display() below
                function  next()
                {
                        if ($this->index < $this->numTuples)
                        {
                                $this->index++;
                                return  1;
                        }
                        else
                        {
                                return  0;
                        }
                }

                // Decrement  index
                function  prev()
                {
                        if ($this->index  >=  0)
                        {
                                $this->index--;
                                return  1;
                        }
                        else
                        {
                                return  0;
                        }
                }

                // Reset  index  to  0 - See also first()
                function  reset()
                {
                        $this->index  =  0;
                }

                // See also reset(). Used in display() below
                function  first()  
                {
                        $this->index  =  0;
                }

                function last()
                {
                        $this->index = $this->numTuples -1 ;
                }

                // Used in display() below
                function showheader($col, $fmt = "")
                {
                        printf("\t< th %s>%s< /th >\n", $fmt, 
                        is_string($col) ? $col : pg_fieldname($this->resultset, $col));
                }

                // Used in display() below
                function showvalue($col, $fmt =  "", $def =  " ")
                {
                        $v = $this->valueof($col);
                        printf( "\t< td %s>%s< /td>\n", $fmt, $v ==  "" ? $def : $v);
                }

                function showurl($col, $fmt =  "")
                {
                        $v = $this->valueof($col);
                        if ( $v !=  "" ) 
                        {
                                printf("\t< td %s> < /td>\n", $fmt);
                        }
                        else 
                        {
                                printf( "\t< td %s>< a href=%s>%s< /a>< /td>\n", $fmt, $v, $v);
                        }
                }

                function display()
                {
                        if (!$this->valid() ) 
                        {
                                return;
                        }

                        printf( "<table cellspacing=1 cellpadding=1 border=1>\n");

                        printf( "<tr>\n");
                        for ($c = 0; $c < $this->cols; $c++ )
                        {
                                $this->showheader($c);
                        }
                        printf( "< /tr>\n");

                        $this->first();
                        while (!$this->eof())
                        {
                                printf( "<tr>\n");

                                for ($c = 0; $c < $this->cols; $c++)
                                {
                                        $this->showvalue($c);
                                }

                                printf( "< /tr>\n");
                                $this->next();
                        }
                        printf("< /table\n");
                }

                // Free  memory  allocated  to  recordset.
                function  free()
                {
                        pg_Freeresult($this->resultset);
                }
        };
}

?>

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