Apex SOQL 每次最多只能查询50000条数据，DML 可以操作的数据更少只有10000条，如果想要处理大量数据，就要考虑使用Batch Apex功能，Batch Apex实现Database.batchable接口
Datebase.Batchable封装了以下三个方法：
1.start方法
代码语言：javascript复制public (Database.QueryLocator | Iterable<sObject>) start(Database.BatchableContext bc) {} 用于收集要操作的数据，然后将数据传到execute()进行具体操作，使用SOQL取得的合计数没有制限，
例如，对于Account来说，最大可以存储5000万件，全部可以返回。
2.execute方法
代码语言：javascript复制public void execute(Database.BatchableContext BC, list<P>){} 对start方法传进来的数据进行处理。
3.finish方法
代码语言：javascript复制public void finish(Database.BatchableContext BC){}batch执行完毕执行，一般用作邮件通知，或者后续操作。
4.Database.executeBatch方法
调用此方法，可以开始执行批处理，
有两个参数，第一个是被执行Batch的Class名，第二个是传入execute方法的Record数
５.实装例
代码语言：javascript复制global with sharing class ExampleUpdateRecordBatch implements Database.Batchable<sObject>,Database.Stateful,Database.AllowsCallouts {
public ExampleUpdateRecordBatch() {
}
global Database.QueryLocator start(Database.BatchableContext BC) {
String queryS = 'SELECT Id,Name FROM Opportunity WHERE DeleteFlg__c = true';
return Database.getQueryLocator(queryS);
}
global void execute(Database.BatchableContext BC, list<sObject> scope) {
Savepoint sp = Database.setSavepoint();
try {
List<Opportunity> newOppList = new List<Opportunity>();
for(Opportunity opportunityItem : (List<Opportunity>)scope) {
opportunityItem.stageName = 'Closed Won';
newOppList.add(opportunityItem);
}
update newOppList;
} catch (Exception ex) {
Database.rollback(sp);
}
}
global void finish(Database.BatchableContext BC) {
}
}
Batch执行：为了测试，我们在匿名框中执行以下代码
代码语言：javascript复制ExampleUpdateRecordBatch batchTest = new ExampleUpdateRecordBatch();
Database.executeBatch(batchTest, 2000);
执行结果：
6.测试类
代码语言：javascript复制@IsTest
private with sharing class ExampleUpdateRecordBatchTest {
@TestSetup
static void initialOrgInfo(){
String strUserName = 'BatchTest001';
Profile profile = [SELECT Id FROM Profile WHERE Name = 'System Administrator' LIMIT 1];
User batchTestUser = new User();
batchTestUser.ProfileId = profile.Id;
batchTestUser.UserName = strUserName '@sample.com';
batchTestUser.FirstName = '';
batchTestUser.LastName = strUserName;
batchTestUser.EMail = 'testuser@sample.com';
batchTestUser.Alias = 'testuser';
batchTestUser.TimeZoneSidKey = 'Asia/Tokyo';
batchTestUser.LocaleSidKey = 'ja_JP';
batchTestUser.EmailEncodingKey = 'ISO-2022-JP';
batchTestUser.LanguageLocaleKey = 'ja';
Database.insert(batchTestUser, false);
PermissionSet permissionSet = [SELECT Id
FROM PermissionSet
WHERE Name = 'Ursus_Park_User'];
PermissionSetAssignment assignmentAss = new PermissionSetAssignment();
assignmentAss.AssigneeId = batchTestUser.Id;
assignmentAss.PermissionSetId = permissionSet.Id;
Database.insert(assignmentAss, false);
}
@IsTest static void testBatch001() {
User runUser = [SELECT ID, UserName FROM User WHERE username='BatchTest001@sample.com'];
List <Opportunity> oppList = new List<Opportunity>();
for(integer i = 0; i<200; i ){
Opportunity oppItem = new Opportunity(Name='testOpportunity' i,
StageName='Perception Analysis',
Ownerid = runUser.Id,
CloseDate = Date.Today(),
DeleteFlg__c = true);
oppList.add(oppItem);
}
insert oppList;
System.runAs(runUser) {
Test.StartTest();
ExampleUpdateRecordBatch reassign = new ExampleUpdateRecordBatch();
ID batchprocessid = Database.executeBatch(reassign, 200);
Test.StopTest();
}
List<Opportunity> oppUpdateList = [SELECT Id,StageName FROM Opportunity WHERE Ownerid = :runUser.Id];
System.assertEquals(200, oppUpdateList.size());
if (oppUpdateList != null && oppUpdateList.size() >0) {
for (Opportunity oppUpdate : oppUpdateList) {
System.assertEquals('Closed Won', oppUpdate.StageName);
}
}
}
}TestClass执行
