First things first, lear the bases off SQL (Structured Query Language). You can do it on any plataform and you tons off sites to learn about, even MA is enough to get started in SQL, then go to specific languages like PL/SQL in Oracle or T-SQL in SQL Server.
I suggest starting off with mySQL its quiet easy, take a look here: http://www.w3schools.com/sql/default.asp .
i want to learn more about database you have good books of it (books are good friend )you have good idea of it
I'd say go with SQL its a good langauge to know and quite easy to learn, or atleast I caught onto it pretty quick.
SQL is language of every databases. Do it first then you can go for another specific RDBMS for your particular purposes.
You can learn sql or oracle and use net or some database related books it will help you to learn .... all the best
Oracle isn't a language, it's a program - and it uses SQL as its language. Dot net isn't a language, it's a framework, and none of its languages are SQL. The language to use for databases that use SQL (IOW, just about all of them) is SQL. There's no other option. The original question is meaningless. What language do you use to speak to someone who only understands French? If you say anything other than "French", you're just wrong. A SQL database only understands the language called SQL.