VISA and serial ports have absolutely
nothing to do with databases. The database VIs in your program are from an old toolkit called SQL Toolkit. This has been replaced with the Database Connectivity Toolkit though if you still have the old one, you can still use it. The difference is that the DCT uses ADO (look up on Microsoft web page) to connect to a database. They both use SQL to insert data and perform queries on a database. The DCT has some higher level functions that make this easier and hide the actual SQL language commands. With the SQL Toolkit, you had to be fairly proficient in the SQL language to get anything done. I have never used the DCT. I used to use the SQL Toolkit and I now use TestStand for my test manager and it has it's own database tools. When I write a standalone LabVIEW application that requires connection to a database, I use LabSQL from
http://www.jeffreytravis.com/lost/labsql.html. It also requires knowledge of SQL but I'm comfortable with that and LabSQL is free.
The connect VI in your example, connects to a data source called "temperaturprov". This may or may not be the name of the actual database. In the Windows control panel, you should have the ODBC administrator. It is here that the data source name is created and pointed to an actual database. The actual database can be located locally or on a server. From your example, there is no way to know.
SQL stands for Structured Query Language. It's a standard for database access. You can have the same queries for different databases (i.e. Access, SQL Server). It has such commands as SELECT (to retrieve rows that meet conditions), INSERT (add rows to a table), UPDATE (modity existing records), etc. I don't have any links ahndy but if you were to Google "SQL tutorial", I'm sure you would find a lot of information.
