Variables

The term date is used to refer to both dates and times.  Dates are represented numerically as floating-point numbers. The integer part of the number represents the date as the number of days since December 30, 1899 (with negative numbers for prior dates), and the fractional part of the number represents the time of day as a fraction of the 24-hour day.

The Object data type can hold a reference to any object.  Using object any type of object can be referenced while you can reference specific types of objects with they type of object, such as referencing a database as a database object or a task as a task object.

A user-defined type (UDT) allows the programmer to define custom data elements that are specifically suited for the data at hand. A UDT can contain two or more elements, each element being a variable or array. UDTs are defined with the Type...End Type statement.

There are situations where an object variable does not refer to any object: It refers to nothing, and VBA has the special keyword Nothing to represent this. An object variable contains Nothing when it has been declared but not yet initialized (has not been assigned an object reference).

Finally, you can (and should) explicitly set an object reference to Nothing when you are finished using the object

A static array has a fixed size or number of elements. You specify the array size when you declare it, and the size cannot change during program execution.  The size will be one more than n because VBA array indexes start by default at 0.

You can use an integer variable or constant as the index.

A dynamic array does not have a fixed size. It can be enlarged or shrunk as needed by code during program execution. A dynamic array is declared by using empty parentheses in the Dim statement.

Before using the array, you must set its size using the ReDim statement.