Abstracting Oracle Connectivity with PHP/OCI8

The Problem

So, you have a huge project that you want to build. It’s been determined
that you want to use PHP, and your backend is Oracle. You’ve installed
Oracle, you’ve installed your web server, and you’ve even gotten PHP to
connect to your Oracle back end to do some simple queries. Now what?

If you are like most lazy programmers, you get something to work, then you
look for a way to do the same thing without having to cut and paste code or
retype the same thing over and over. Well, I’ve found that connecting to
Oracle is typically done the same way over and over. So, I’ve written some
functions to help me run some queries without the drudgery of repetition.
Take these functions, roll them into a PHP class, and voila! … easy
PHP/OCI8!

Oracle How-To – The Hard Way

To do any database calls, the typical process is as follows:

1. Connect to the database (OCILogon)
2. Parse a SQL statement (OCIParse)
3. Bind Variables if necessary (OCIBindByName)
4. Execute query (OCIExecute)
5. Fetch Results

Meanwhile, during each step in this process you need to check for errors
and handle them appropriately. You might encounter an error during the
OCILogon or during the OCIParse or during…well, you get the point.

Abstract the SQL Query Calls

What I’ve attempted to do is abstract this process into a single function
prototyped as follows:

    /** PUBLIC (stmt_hndl)
     * Returns the statement handle created from the execution of the SQL
     * query.  If the statement fails, the method returns (false) and the
     * error is available in $this->ERROR.
     */
    function query($sid, $sql, &$bargs) {
    ...
    }

You may notice that this function takes three arguments: SID, SQL, and
Bind Args.

SID – The SID is the Oracle database you want to connect
to. You’ll notice that I’m not sending the username and password. You’ll see
why when you read the next section on abstracting the OCILogin.

SQL – The SQL parameter is the SQL statement you want to
run. This is a SELECT, INSERT, UPDATE command…whatever. You might even be calling
a chunk of PL/SQL code. Regardless of the query, this function can handle it.

Bind Args – The third parameter is an array of Bind
arguments. Bind arguments allow you to pass IN/OUT variables to your SQL
queries and enable a syntax of doing queries that don’t require you to escape
all your inputs. Once I discovered the use of bind arguments, my Oracle world
was forever changed.

Abstract the OCILogin (Database, Username, and Password)

Another common problem in the Oracle connectivity world is where the passwords
are stored. I’ve seen websites where Oracle usernames and passwords were
sprinkled all over the place in this script and in that class. This makes it
very difficult to maintain passwords or let alone go through the nightmare of
trying to change one! What I’ve done is create another function to act as
a password vault. I store the Oracle SID, username, and password as an array
of three values which can be fetched by a given key. This way any time I want
to connect to the “XYZ” database, I simply ask this function for the
Account database name, username and password and get them. Here is a prototype
for that function:

    /** PRIVATE
     * Returns the SID, USERNAME, and PASSOWORD used to connect to a given
     * Oracle database.
     */
    function getDBAuth($sid) {
    ...
    }