Answer / chandonline

Basic difference between primary key and unique is that primary key is used to define a table in other tables for preventing data from anomalies,and unique key is used in a table to apply unifications among different values or columns of a tables and only in that table obviously.Their is no usage of unique key outward a table but primary key is often used to make relations between other tables.

Answer / ashish tyagi

The basic difference between primary key and unique key is that unique key allows null value but primary key did not allow null value.

In which database can extended stored procedures be added?

0 Answers  

---

what is the use of foreginkey

2 Answers  

---

Explain the rollup operator?

0 Answers  

---

Write short notes on XSU and JAVA

1 Answers  

---

1. Using the XML Document below, with the URI “recipe.xml” define the following queries in XQuery: a.) Give the names of all breakfast in the menu. b.) Select breakfasts that have price lower than $7.00? <?xml version="1.0"?> <breakfast_menu> <food> <name>Belgian Waffles</name> <price>$5.95</price> <description> two of our famous Belgian Waffles with plenty of real maple syrup </description> <calories>650</calories> </food> <food> <name>Strawberry Belgian Waffles</name> <price>$7.95</price> <description> light Belgian waffles covered with strawberries and whipped cream </description> <calories>900</calories> </food> <food> <name>Berry-Berry Belgian Waffles</name> <price>$8.95</price> <description> light Belgian waffles covered with an assortment of fresh berries and whipped cream </description> <calories>900</calories> </food> <food> <name>French Toast</name> <price>$4.50</price> <description> thick slices made from our homemade sourdough bread </description> <calories>600</calories> </food> <food> <name>Homestyle Breakfast</name> <price>$6.95</price> <description> two eggs, bacon or sausage, toast, and our ever-popular hash browns </description> <calories>950</calories> </food> </breakfast_menu>

0 Answers  

---

What is the database development process?

0 Answers  

---

Explain the role of indexing in databases?

0 Answers  

---

How to customize error conditions.

0 Answers  

---

What you can do to remove data from the cache and query plans from memory for testing the performance of a query repeatedly?

0 Answers  

---

Explain about query and reporting.

0 Answers  

---

Given an employee table, how would you find out the second highest salary?

9 Answers  

---

How to create an external table.

1 Answers  

---