PHP Data Abstraction

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PHP Data Abstraction

• Clean out the CRUD

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Intro

• PHP  allows us to very easily and quickly connect
  to, query and return results from any number of
  different databases, including mysql, postgresql,
  sqllite and even MSSQL. This flexibility in php
  makes it a powerful tool, and unfortunately a
  quick way to get into trouble.   We have all
  written Create, Retrieve, Update, Delete code in
  PHP before, whether in a form, an administration
  system for news articles, or maybe a home grown
  e-commerce system.  Having written this code you
  have at some point had to go back in to debug,
  add features, change functionality.   Typically
  most of these interactions with your own code are
  somewhat painless (assuming comments and well
  formated code) and you can trace your way through
  well enough to make changes or to troubleshoot.

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What is Data Abstraction

• A database abstraction layer provides a
  database-independent interface to developers
  working on different databases. Perl has one, and
  now PHP has one too, courtesy of PEAR and ADOdb.
  Though an abstraction layer can take a little
  getting used to, it offers tremendous benefits in
  the long run, especially if you expect platform
  or database changes during the development cycle.
  Using an abstraction layer can significantly
  reduce the amount of time you spend porting your
  code over from one database to another.
• The available PHP abstraction layer currently
  includes support for a number of different
  database types, including MySQL, PostgreSQL,
  Oracle, Sybase and ODBC. In addition to
  frequently-used methods for executing queries and
  fetching resultsets, the PEAR abstraction layer
  also supports pre-prepared queries, transactions
  and customized error handling. A number of
  miscellaneous utility functions are also included
  to assist in query execution and data retrieval.

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ADOdb

• ADOdb is a database abstraction layer for PHP.
  There are many advantages of using a database
  abstraction layer instead of the native database
  functions in PHP.
• The main advantage is that your project can
  support multiple databases. You don't have to
  lock your users into the database you prefer,
  instead they can use the database they prefer to
  use. This increases the potential user base for
  your project.
• Another key advantage is that it provides you
  with a standard, unified set of commands to use
  with all databases that PHP supports. If you
  change databases you don't have to deal with
  learning different functions each time. Also, due
  to this, the data is returned in the same format
  each time no matter which database you are using.
  ADOdb returns the data as a two-dimensional array
  which you can manipulate any way you want. Using
  a two-dimensional array gives you much more
  flexibility to do what you want with the data.

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Why this is Good

• It reduces the coupling between your object
  schema and your data schema, increasing your
  ability to evolve either one.
• It implements all data-related code in one place.
• It simplifies the job of application programmers
  and code maintainers.
• It allows application programmers to focus on
  the business problem in one area while focusing
  on data access on the database in another.
• It gives you a common place to implement
  data-oriented business rules.
• It can takes advantage of specific database
  features, increasing application performance.
• Makes changing database schemas or even database
  vendors much easier to implement

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Different Types

• People sometimes say SQL abstraction layer or
  database interface fairly loosely, assuming
  everyo knows what they mean. Not so Ive seen
  at least four distinct meanings in common usage
• 1. A software library to connect to a database
  server and issue queries, fetch results etc.
• 2. A software library to present a common API
  to different database servers.
• 3. A software library to automatically
  generate portable SQL queries.
• 4. A software library to map Object-Oriented
  Programming to a relational database
  (Object-Relational Mapping, or ORM)

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Lets look
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Looking
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With Smarty !