There are 8 data types in PHP which are used to construct the variables:
1. Integers - are whole numbers without a decimal point, like 4195.
2. Doubles - are floating-point numbers, like 3.14486 or 49.1.
3. Booleans - have only two possible values either true or false.
4. Null - is a special type that only has one value:Null.
5. Strings - are sequences of characters.
6. Arrays - are named and indexed collection of other values.
7. Objects - are instances of programmer-defined classes, which can package up both other kinds of values and functions that are specific to the class.
8. Resources- are spacial varibles that hold references to resources external to PHP.