What Can SQL do?
- SQL can execute queries against a database
- SQL can retrieve data from a database
- SQL can insert records in a database
- SQL can update records in a database
- SQL can delete records from a database
- SQL can create new databases
- SQL can create new tables in a database
- SQL can create stored procedures in a database
- SQL can create views in a database
- SQL can set permissions on tables, procedures, and views
SQL is a Standard - BUT....
Although SQL is an ANSI/ISO standard,
there are different versions of the SQL language.
However, to be compliant with the ANSI standard,
they all support at least the major commands (such as SELECT, UPDATE, DELETE, INSERT, WHERE) in a similar manner.
Before SQL comes into play ...
One will have designed multiple entity classes and populated them with records to creat entity sets
Then, SQL may be used to retrieve needed data from the entity sets
We have used SQL terminology in describing Excel filters, but now we will try to work with SQL itself
We may use the W3Schools SQL tutorial to get a sense of SQL and how it works.