Apex is a strongly typed language, every variable in the apex must be declared with a specific data type. All apex variables were initially assigned a null value.

You can read the previous article Salesforce Apex Tutorial – Chapter 3: Apex Examples and next article Salesforce Apex Tutorial – Chapter 5: Apex Variables.

Here is a list of data types supported by Apex:

1. Primitive (Integer, Double, Long, Date, DateTime, String, ID, Blob, and Boolean).
2. Collections (Lists, Sets, and Maps).
3. sObject
4. Enums
5. Classes, Objects, and Interfaces

Let’s discuss the Primitive data types, sObject, and enums in detail.

Primitive Data Types:

• Integer:
  It is a 32 bit number that does not contain any decimal points. Its value ranges between -2,147,483,648 and 2,147,483,647. Example:

The system.debug statement prints the value of the quantity variable.

• Boolean:
  A boolean variable can only be assigned a true, false, or null value. A boolean variable is used in control statements to determine the flow of a program. Example:

In the above statement, we have declared the isCheck variable and initialized it to true.

• Date:
  A variable of date datatype is used to store a date. A date variable doesn’t have any information about time. A DateTime variable can be used to store time along with the date. Example:

• Long:
  It is a 64-bit number that does not contain any decimal points. This data type should be used to assign a value wider than the range supported by the integer. Example:

• Enum:
  An enum type is a special data type that enables a variable to be a set of predefined constants. The variable must be equal to one of the values that have been predefined for it.
  Example:
  Declaring an Enum for compass directions.

• sObject:
  It is a special data type in the apex. A sObject variable represents a row of data and can only be declared in Apex using the SOAP API name of the object.
  Example: