Advertisements
Advertisements
प्रश्न
______ is a non-key attribute, whose values are derived from the primary key of some other table.
विकल्प
Primary Key
Foreign Key
Candidate Key
Alternate Key
उत्तर
Foreign Key is a non-key attribute, whose values are derived from the primary key of some other table.
Explanation:
- Primary Key - It is used to uniquely identify the tuples in a relation.
- Foreign Key - It is used to represent the relationship between two tables/relations and its value is derived from the primary key of some other table.
- Candidate Key - refers to the set of all attributes which can uniquely identify records in a relation.
- Alternate Key - It is a candidate key that has not been selected to be the primary key.
So, the correct answer is Foreign Key.
APPEARS IN
संबंधित प्रश्न
Each table comprises of ______ and ______.
Case Based
Consider the table STUDENT with the following detail.
| STU_ID | NAME | STREAM | MARKS | CLASS |
| 1. | Aditya | Science | 87.5 | 12A |
| 2. | Vikram | Commerce | 88.7 | 12B |
| 3. | Astha | Humanities | 76.8 | 12C |
| 4. | Varsha | Science | 79.5 | 12A |
| 5. | Kanishka | Science | 77.9 | 12A |
| 6. | Anand | Commerce | 86.7 | 12B |
Now answer the question given below:
Command to select all Science students from the table STUDENT
Case Based
Consider the table STUDENT with the following detail.
| STU_ID | NAME | STREAM | MARKS | CLASS |
| 1. | Aditya | Science | 87.5 | 12A |
| 2. | Vikram | Commerce | 88.7 | 12B |
| 3. | Astha | Humanities | 76.8 | 12C |
| 4. | Varsha | Science | 79.5 | 12A |
| 5. | Kanishka | Science | 77.9 | 12A |
| 6. | Anand | Commerce | 86.7 | 12B |
Now answer the question given below:
Delete records that belongs to 'Humanities' stream.
Which of the following command is used to remove a relation from an SQL database?
A tuple in RDBMS is referred to as ______ of a table.
Which of the following is not an RDBMS?
What is not true with respect to the create table statement?
What statement will you give to view the structure of a table?
How will you add a primary key to a relation?
How will you add two columns coll and col2(composite key) as primary key to a relation?
How will you add a foreign key to a relation?
Raju's date of birth is 21/06/2006. How will his date be added to database?
Differentiate between the following statement:
ALTER and UPDATE
A shop called Wonderful Garments which sells school uniforms maintains a database SCHOOLUNIFORM as shown below. It consisted of two relations - UNIFORM and COST. They made UniformCode the primary key for UNIFORM relations. Further, they used UniformCode and Size to be composite keys for COSTrelation. By analyzing the database schema and database state, specify SQL queries to rectify the following anomalies.
- M/S Wonderful Garments also keeps handkerchiefs of red colour, medium size of Rs. 100 each.
- INSERT INTO COST (UCode, Size, Price) values (7, 'M', 100);
When the above query is used to insert data, the values for the handkerchief without entering its details in the UNIFORM relation are entered. Make a provision so that the data can be entered in the COST table only if it is already there in the UNIFORM table. - Further, they should be able to assign a new UCode to an item only if it has a valid UName. Write a query to add appropriate constraints to the SCHOOLUNIFORM database.
- Add the constraint so that the price of an item is always greater than zero.
Suppose your school management has decided to conduct cricket matches between students of Class XI and Class XII. Students of each class are asked to join any one of the four teams – Team Titan, Team Rockers, Team Magnet, and Team Hurricane. During summer vacations, various matches will be conducted between these teams. Help your sports teacher to do the following:
- Create a database “Sports”.
- Create a table “TEAM” with the following considerations:
i) It should have a column TeamID for storing an integer value between 1 to 9, which refers to the unique identification of a team.
ii) Each TeamID should have its associated name (TeamName), which should be a string of length not less than 10 characters. - Using table level constraint, make TeamID the primary key.
- Show the structure of the table TEAM using a SQL statement.
- As per the preferences of the students four teams were formed as given below. Insert these four rows in the TEAM table:
Row 1: (1, Team Titan)
Row 2: (2, Team Rockers)
Row 3: (3, Team Magnet)
Row 3: (4, Team Hurricane) - Show the contents of the table TEAM using a DML statement.
- Now create another table MATCH_DETAILS and insert data as shown below. Choose appropriate data types and constraints for each attribute.
| Table: MATCH_DETAILS | |||||
| MatchID | MatchDate | FirstTeamID | SecondTeamID | FirstTeamScore | SecondTeamScore |
| M1 | 2018-07-17 | 1 | 2 | 90 | 86 |
| M2 | 2018-07-18 | 3 | 4 | 45 | 48 |
| M3 | 2018-07-19 | 1 | 3 | 78 | 56 |
| M4 | 2018-07-19 | 2 | 4 | 56 | 67 |
| M5 | 2018-07-18 | 1 | 4 | 32 | 87 |
| M6 | 2018-07-17 | 2 | 3 | 67 | 51 |
Which of the following commands will delete the table from the MYSQL database?
Write the command to view all tables in a database.
Write the command to view all databases.
Name any two DDL commands.
Ms Shalini has just created a table named “Employee” containing columns Ename, Department and Salary. After creating the table, she realized that she has forgotten to add a primary key column in the table. Help her in writing an SQL command to add a primary key column EmpId of integer type to the table Employee.
Thereafter, write the command to insert the following record in the table:
EmpId- 999
Ename- Shweta
Department: Production
Salary: 26900