DBMS اسئلة واجوبة المقابلات
Test your skills through the online practice test: DBMS Quiz Online Practice Test
فروقات ذات صلة
سؤال 51. What is Domain-Key Normal Form?
A relation is said to be in DKNF if all constraints and dependencies that should hold on the the constraint can be enforced by simply enforcing the domain constraint and key constraint on the relation.
هل هذا مفيد؟
اضف تعليقا
عرض التعليقات
سؤال 52. What are partial, alternate, artificial, compound and natural key?
1. Partial Key: It is a set of attributes that can uniquely identify weak entities and that are related to same owner entity. It is sometime called as Discriminator.
2. Alternate Key: All Candidate Keys excluding the Primary Key are known as Alternate Keys.
3. Artificial Key: If no obvious key, either stand alone or compound is available, then the last resort is to simply create a key, by assigning a unique number to each record or occurrence. Then this is known as developing an artificial key.
4. Compound Key: If no single data element uniquely identifies occurrences within a construct, then combining multiple elements to create a unique identifier for the construct is known as creating a compound key.
5. Natural Key: When one of the data elements stored within a construct is utilized as the primary key, then it is called the natural key.
هل هذا مفيد؟
اضف تعليقا
عرض التعليقات
سؤال 53. What is indexing and what are the different kinds of indexing?
Indexing is a technique for determining how quickly specific data can be found.
Types:
1. Binary search style indexing
2. B-Tree indexing
3. Inverted list indexing
4. Memory resident table
5. Table indexing
هل هذا مفيد؟
اضف تعليقا
عرض التعليقات
سؤال 54. What is system catalog or catalog relation? How is better known as?
A RDBMS maintains a description of all the data that it contains, information about every relation and index that it contains. This information is stored in a collection of relations maintained by the system called metadata. It is also called data dictionary.
هل هذا مفيد؟
اضف تعليقا
عرض التعليقات
سؤال 55. What is meant by query optimization?
The phase that identifies an efficient execution plan for evaluating a query that has the least estimated cost is referred to as query optimization.
هل هذا مفيد؟
اضف تعليقا
عرض التعليقات
الاكثر فائدة حسب تقييم المستخدمين:
- What is database or database management systems (DBMS)?
- What is SQL?
- What's the difference between file and database? Can files qualify as a database?
- What are E-R diagrams?
- Whats difference between DBMS and RDBMS?