Property Attributes

Attributes provide additional metadata or declarative information to your codebase.  This metadata can be queried at run-time/design-time, using reflection, in order to control logic flow, provide additional descriptive information or define additional behaviour when considering special circumstances; to name a few.

In your specific case, the attributes are being used to associated the property with a database column.  In this way, the Entity Framework (assumption) has all the information it needs in order to maintain a cohesive relationship between the CITY_STATE property and the CITY_STATE column in the defined table of the defined database.

A small example -

Imports System.Reflection
Imports System.Runtime.CompilerServices

Module Module1
	Sub Main()
		For Each pair In Assembly.GetEntryAssembly().EntryAssemblyMetaData()
			For Each value In pair.Value
				Console.WriteLine($"{pair.Key}: {value}")
			Next
		Next
		Console.ReadLine()
	End Sub
End Module

Module Extensions
	<Extension()>
	Public Function EntryAssemblyMetaData([assembly] As Assembly) As Dictionary(Of String, List(Of String))
		Return (From [attribute] In assembly.GetCustomAttributes(False).Cast(Of Attribute)
				From [property] In attribute.GetType().GetProperties()
				Where Not [property].Name.Equals("TypeId", StringComparison.OrdinalIgnoreCase)
				Group CType([property].GetValue(attribute, Nothing), String) By [Key] = attribute.GetType().Name Into properties = Group
				Select New With {[Key], properties}).ToDictionary(Function(x) x.Key, Function(y) y.properties.ToList())
	End Function
End Module

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Which produces the following output -Most of the metadata that I queried, originates from the AssemblyInfo.vb file -
-saige-