Oracle Certification problems
- 1. Can?t update primary table?s primary key if row being modified has related rows in secondary table once referential integrity is enforced
Options- A. TRUE
- B. FALSE Also asked in: Database Administrator
Correct Answer: TRUE
- 2. A subquery in an sql select statement. Also asked in: Analyst, Database Administrator, IT Trainer, Project Manager
Correct Answer: A Subquery or Inner query or a Nested query is a query within another SQL query and embedded within the WHERE clause Subqueries are most frequently used with the SELECT statement The basic syntax is as follows:: SELECT column_name [, column_name ] FROM table1 [, table2 ] WHERE column_name OPERATOR (SELECT column_name [, column_name ] FROM table1 [, table2 ] [WHERE]) A subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved Subqueries can be used with the SELECT, INSERT, UPDATE, and DELETE statements along with the operators like =, <, >, >=, <=, IN, BETWEEN, etc There are a few rules that subqueries must follow ? 1 Subqueries must be enclosed within parentheses 2 A subquery can have only one column in the SELECT clause, unless multiple columns are in the main query for the subquery to compare its selected columns 3 An ORDER BY command cannot be used in a subquery, although the main query can use an ORDER BY The GROUP BY command can be used to perform the same function as the ORDER BY in a subquery 4 Subqueries that return more than one row can only be used with multiple value operators such as the IN operator 5 The SELECT list cannot include any references to values that evaluate to a BLOB, ARRAY, CLOB, or NCLOB 6 A subquery cannot be immediately enclosed in a set function 7 The BETWEEN operator cannot be used with a subquery However, the BETWEEN operator can be used within the subquery
- 3. The SQL keyword BETWEEN is used:
Options- A. for ranges
- B. as a wildcard
- C. to limit the columns displayed
- D. All the above Also asked in: Analyst, Database Administrator, IT Trainer, Project Manager, Software Architect
Correct Answer: for ranges
Explanation:
In SQL, BETWEEN Keyword is used for ranges like Number Ranges, Date Ranges, etc...
- 4. Data integrity constraints are used to
Options- A. Ensure that duplicate records are not entered into the table
- B. Prevent users from changing the values stored in the table
- C. Control who is allowed access to the data
- D. Improve the quality of data entered for a specific property like table column Also asked in: Analyst, Database Administrator, IT Trainer
Correct Answer: Improve the quality of data entered for a specific property like table column
Explanation:
Integrity constraints are used to ensure accuracy and consistency of data in a relational database. Data integrity is handled in a relational database through the concept of referential integrity. Many types of integrity constraints play a role in referential integrity (RI).
Hence, Data integrity constraints are used to Improve the quality of data entered for a specific property i.e, table column.
- 5. What is an Extension of Entity Type? Also asked in: Analyst, Database Administrator, IT Trainer, Project Manager
Correct Answer: The collections of entities of a particular Entity Type are grouped together into an entity set
- 6. Which packages contain the JDBC classes?
Options- A. java.sql
- B. java.sl
- C. java.jd
- D. java.jdbc Also asked in: Database Administrator, IT Trainer, Software Architect
Correct Answer: java.sql
Explanation:
The Java packages which contain JDBC classes and interfaces is Java.SQL.
Programming
Copyright ©CuriousTab. All rights reserved.