السلام عليكم
many of Programming languages can be used With GIS Applications Like C# ,VB.Net,Java
but the point is i think you still in a need to know about the GIS concepts and to know also the technologies used to deal with GIS data then you can decide with technology you will use and which Programing Language
and my advice to you to learn about Esri ArcGIS products and to learn VB.Net or C# as these are the easiest to learn as I think
abou the GIS data , you can classify the GIS data to 2 main types (Raster & Vector) each one used for different purpose
1- Vector Data : the vector data is the Geometric data which store the shape of an object like street or Parcel or point of interest like hospital or restaurant
2 - Raster Data: this is simply the images wich you can get from the satellite or from air photos or scanned paper maps

there is many ways to store the GIS Data and there is many GIS Programs can deal with issue like ArcGIS, Geomedia, erdas Immagin, Map Info
I will take about the ArcGIS Program and the ways to store vector data,
from many years we used to use Coverages then shapefiles to store GIS data with ArcGIS but now we use GeoDatabase
the GeoDatabase can be personal Geodatabase or Enterprise Geodatabase
the personal geodatabase is simply Access file but you have to create it from the ArcGis and also deal with it from the ArcGIS
the Enterprise GeoDatabase can be Oracle or SQl or any else
there is one question....... what is the difference between the Database and the GeoDatabse?
the answer is the Geo Database is a database BUT it can store a GIS data
another question, how can the GeoDatabse store GIS Data?
it can store GIS Data it tables which contains a field from type Geometry
can store the shape of an object and this table called (feature Class) like i said before the street
for example if we need to store the streets with its names we can create a feature class with the Geometry field that can store Line and with a string field that can store the names of the street, then using the ArcGIS you can edit this feature class by drawing the streets and enter the names of each street

if you need to learn more about this you can take the courses of Introduction to ArcGIS 1 & Introduction to ArcGIS 2