Apex Batch class is a powerful feature of Salesforce that allows you to process large amounts of data efficiently and asynchronously. It's a great tool to have in your arsenal when working with large datasets or performing complex operations on your data. In this blog post, we'll cover the basics of Apex Batch classes, including how to create one, how to use it, and some best practices to keep in mind when working with them.
What is an Apex Batch Class?
An Apex Batch class is a special type of Apex class that allows you to perform a specific operation on a large number of records. The records are processed in small groups, called batches, which allows for better performance and scalability. This is particularly useful when working with large datasets or when performing complex operations on your data.
Creating an Apex Batch Class
Creating an Apex Batch class is quite simple. The first step is to create a new Apex class and extend it from the "Database.Batchable" interface. This interface requires you to implement three methods:
start(): This method is called when the batch job is first executed and is used to define the query that retrieves the records to be processed.
execute(): This method is called for each batch of records retrieved by the query defined in the start method. It contains the logic to process the records.
finish(): This method is called after all batches have been processed and is used to perform any final operations or cleanup tasks.
Here is an example of a basic Apex Batch class:
global class MyBatchClass implements Database.Batchable<sObject> {
global Database.QueryLocator start(Database.BatchableContext bc) {
// Define the query to retrieve the records to be processed
return Database.getQueryLocator([SELECT Id FROM Account]);
}
global void execute(Database.BatchableContext bc, List<sObject> scope) {
// Process the records
for (sObject record : scope) {
// Perform operations on the record
}
}
global void finish(Database.BatchableContext bc) {
// Perform any final operations or cleanup tasks
}
}Using an Apex Batch Class
Once you have created your Apex Batch class, you can use it to process your records by calling the Database.executeBatch() method. This method takes an instance of your batch class as a parameter, along with the number of records to be processed in each batch.
Here is an example of how to use the MyBatchClass example above:
MyBatchClass batch = new MyBatchClass();
Database.executeBatch(batch, 200);Best Practices
When working with Apex Batch classes, there are a few best practices to keep in mind:
Keep the number of records processed in each batch as low as possible to reduce the memory usage and avoid hitting governor limits.
Avoid using SOQL or DML statements inside a loop to avoid hitting governor limits.
Use the Database.Stateful interface to maintain state across different batches.
Test your Apex Batch classes thoroughly to ensure they work correctly and avoid any errors.
Use try-catch blocks to handle any errors that may occur during the execution of the batch.
Apex Batch Class Governor Limits
Apex batch classes have governor limits, which are limits on the number of records, database operations, and other resources that a single batch Apex execution can use. Some of the important governor limits for batch Apex include:
The maximum number of records that can be retrieved by a single query is 50,000.
The maximum number of records that can be processed by a single batch Apex execution is 10,000.
The maximum number of callouts (to external systems) made by a batch Apex class is 100.
The maximum number of executed script statements for a batch Apex class is 10,000,000.
The maximum number of records that can be updated by a single DML statement is 200.
It's important to keep these limits in mind when designing batch Apex classes, and to design your classes to stay within these limits to avoid exceeding them and causing the batch job to fail.
In conclusion, Apex Batch classes are a powerful tool that can help you perform large and complex operations in Salesforce in a manner that doesn't exceed governor limits. With the help of this blog post and the provided example, you should have a good understanding of how to get started with Apex Batch classes and how to use them in your own Salesforce org.
Comentarios