DBMS (Database) Quiz

DBMS is the standard acronym for Database Management System, which is software that manages databases. It provides an interface for users to create, maintain, and access databases efficiently.

Database normalization eliminates redundant data by organizing it logically, which makes storage more efficient. It breaks large tables into smaller, related ones to reduce duplication and improve data integrity.

The SELECT clause is the fundamental requirement for any SQL query intended to retrieve data. While WHERE, ORDER BY, and JOIN are common for filtering and organizing, they are optional; a valid query must start with SELECT to identify the data to be fetched.

SQL's SELECT clause has no limitation on the number of fields specified. You can select one field, multiple fields, or all fields in a single query depending on your requirements.

The SELECT clause specifies which columns (fields) to retrieve, not the number of records. The number of records returned is determined by the WHERE clause and the data present in the table. Thus, it can return as many records as match the criteria.

The asterisk (*) is the standard SQL wildcard character used in SELECT statements to retrieve all columns from a table. It saves listing individual field names when you need complete row data.

The WHERE clause filters records returned by SQL queries based on specified conditions. It restricts the result set to only those rows that meet the criteria, reducing output to relevant records.

SQL supports INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN, and CROSS JOIN as valid join types. MIDDLE JOIN is not a standard SQL join type and does not exist in SQL syntax.

The ORDER BY clause in SQL is used to specify the sequence in which the resulting records (rows) are returned. While it uses field names to determine the sort criteria, the actual items being sorted and rearranged in the output are the records themselves.

A connection object needs to know where the database is located (server address or file path), what type of database it is (SQL Server, Oracle, etc.), and may need query information to establish proper communication. All three properties are essential components for creating a valid database connection.