How does the class map perform?
[SELECT Id,(SELECT Id FROM Opportunities) FROM Account WHERE Id IN :Trigger.New]);
I am getting this code when I am trying to learn Triggers. Can I get any explanation regarding this code?
Class maps are used to configure match packet criteria on a match-any basis. Whatever action is associated with the first-matched class map is referred to as the action done by the system.
Apex map class is considered to be a unique Apex idiom. It contains constructors which have several sObjects that result from a SOQL query. A class map’s constructor populates a map with the Ids of the sObjects and sObjects. Though you can find various uses of class maps, one of its main works is providing answers when someone asks a question using related objects. You will need to have fast access to some related objects based on the Ids. An Apex map can assist you in keeping records of the queries so that you do not have to iterate through a list. It helps to make the process easy and efficient.