class Database extends OneDatabase I'm trying to conform to the Zend Coding Standard as well.

EDIT 2:

&lt;?php

/**
 *    Input   :   Query request
 *    Output  :   A row or a list of rows
 *    Notes   :
 *
 *    Provides escaping and binding via PDO library
 *    Consolidates PDO to use a single calling mechanism
 *    Consolidates all queries to an associative array
 *    Mysqli available for those who wish to implement
 */

class Database extends OneDatabase
{
    private $dbResource;
    public function __construct()  
    {
        $this-&gt;dbResource = oneDatabase::_get();
    }
    public function getResource()
    {
        return $this-&gt;dbResource;
    }
    protected $_sqlArray = array(
        "signin_pass" =&gt; "SELECT pass FROM cr WHERE email=?",
        "signin_validate" =&gt; "SELECT email,pass FROM cr WHERE email=? AND pass=?",
        "signin_flname" =&gt; "SELECT flname FROM cr WHERE email=?",
        "signup_check" =&gt; "SELECT * FROM cr WHERE email=?",  
        "signup_insert" =&gt; "INSERT INTO cr VALUES (?,?,?)",
        "signup_site1" =&gt; "INSERT INTO bo VALUES ('Facebook','http://www.facebook.com','',?)",
        "signup_site2" =&gt; "INSERT INTO bo VALUES ('Twitter','http://www.twitter.com','',?)",
        "bookmark_delete" =&gt; "DELETE FROM bo WHERE name=? AND email=? LIMIT 1",
        "bookmark_insert" =&gt; "INSERT INTO bo VALUES (?, ?,'', ?)",
        "bookmark_model" =&gt; "SELECT * FROM bo WHERE email=? ORDER BY name ASC",
        "tweet_insert" =&gt; "INSERT INTO tw VALUES (?,?,?,?)",
        "tweet_model" =&gt; "SELECT * FROM tw ORDER BY time DESC LIMIT 7",
        "create_bookmark" =&gt; "CREATE TABLE bookmark(name VARCHAR(64), url VARCHAR(256), tag VARCHAR(256), id INT)",
        "create_credentials" =&gt; "CREATE TABLE credentials(id INT NOT NULL AUTO_INCREMENT, flname VARCHAR(60), email VARCHAR(32), pass VARCHAR(40), PRIMARY KEY(id))",
        "create_tweet" =&gt; "CREATE TABLE tweet(id INT NOT NULL AUTO_INCREMENT, flname VARCHAR(60), email VARCHAR(32), pass VARCHAR(40), PRIMARY KEY(id))"
    );
    public function _pdoQuery($fetchType, $queryType, $parameterArray) 
    {
        $query=$this-&gt;_sqlArray[$queryType];
        eval("\$query = \"$query\";");
        if($parameterArray==0)
        {
            $results = oneDatabase::$_database-&gt;query($query);
            return $results;
        }
        oneDatabase::$_database-&gt;quote($query);
        $pdoStatement = oneDatabase::$_database-&gt;prepare($query);
        $pdoStatement-&gt;execute($parameterArray);
        if($fetchType=='none')
        {
            $results=NULL;
        }
        else if($fetchType=='single')
        {
            $results = $pdoStatement-&gt;fetch(PDO::FETCH_ASSOC);
        }
        else if($fetchType=='multiple')
        {
            $results = $pdoStatement-&gt;fetchAll();
        }
        return $results;
    }
    protected function _mysqliQuery($aquery) 
    {
        return oneDatabase::$_database-&gt;query($query);
    }
}
The good thing about this code is your bracing style which is applied consistently and is visually appealing.  Now on to some improvements:

This code does not implement a Database.  (You have called the class Database, but it does not resemble something that looks like a database).  This class does not really have a good purpose.  If you are going to write a database class it should handle database type things.  Like transactions or methods for select, insert and delete statements etc.

Some other things:


It is not easy to re-use the code.
It contains hard coded values.
It breaks up a logical separation of concerns for your program.
Don't use eval - it is not good for your application security:
eval("\$query = \"$query\";");
oneDatabase::$_database can be replaced by $this->_database as you
are extending that class.
mysqli is mixed in with PDO.  Just use PDO.
databaseCopy is not required
method access should be specified (public, protected, private)


In summary, I think you should re-think your design.