Hi,

Apex Code is the Force.com programming language used to write custom, robust business logic. As with any programming language, there are key coding principles and best practices that will help you write efficient, scalable code.

Best Practice #1: Querying Large Data Sets

The total number of records that can be returned by SOQL queries in a request is 50,000. If returning a large set of queries causes you to exceed your heap limit, then a SOQL query for loop must be used instead. It can process multiple batches of records through the use of internal calls to query and queryMore.

Best Practice #2: Bulkify your Code

Bulkifying Apex code refers to the concept of making sure the code properly handles more than one record at a time. When a batch of records initiates Apex, a single instance of that Apex code is executed, but it needs to handle all of the records in that given batch.

Best Practice #3: Avoid SOQL Queries inside FOR Loops

 A common mistake is that queries are placed inside a for loop. There is a governor limit that enforces a maximum number of SOQL queries. When queries are placed inside a for loop, a query is executed on each iteration and the governor limit is easily reached. Instead, move the SOQL query outside of the for loop and retrieve all the necessary data in a single query.

 Note : Executing queries or DML operations within an iteration adds risk that the governor limits will be exceeded.

Best Practice #4: Using Collections, Streamlining Queries, and Efficient For Loops

 It is important to use Apex Collections to efficiently query data and store the data in memory. A combination of using collections and streamlining SOQL queries can substantially help writing efficient Apex code and avoid governor limits.

 Best Practice #5: Streamlining Multiple Triggers on the Same Object

 It is important to avoid redundancies and inefficiencies when deploying multiple triggers on the same object. If developed independently, it is possible to have redundant queries that query the same dataset or possibly have redundant for statements.

Note that it is very important to detail exactly how governor limits are applied when multiple triggers are deployed on the same object.

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