Books and articles about DBMS & SQL

Electronical books and articles about DBMS and SQL language: query oprimization; administration and DBMS optimization tunung; examples SQL operators using. Testing and certification about SQL DML. Self-instruction manual and problem book by SQL

SQL language, DBMS, databases, SQL queryes tuning, queryes, performance tuning, books, articles, MS SQL Server, SQL Server, MySQL, SQL certificaton, distance learning