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प्रश्न
The code given below deletes the record from the table employee, which contains the following record structure:
E_code - StringE_name - StringSal - IntegerCity - String
Note the following to establish connectivity between Python and MySQL:
- Username is
root - Password is
root - The table exists in a MySQL database named
emp. - The details
(E_code, E_name, Sal, City)are the attributes of the table.
Write the following statements to complete the code:
Statement 1 – to import the desired library.
Statement 2 – to execute the command that deletes the record with E_code as 'E101'.
Statement 3 – to delete the record permanently from the database. ____________
import ____________ as mysql #Statement1
def delete():
mydb=mysql.connect(host="localhost",use r="root",
passwd="root",database="emp")
mycursor=mydb.cursor()
____________ #Statement 2
____________ #Statement 3
print ("Record deleted") उत्तर
Statement1: mysql.connector
Statement2: mycursor.execute("Delete from emp where E_code='E101'")
Statement3: mydb.commit() 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.
To know the names of existing databases, we use the statement:
What is not true with respect to the create table statement?
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?
Which statement is used to remove a table from the database?
Differentiate between the following statement:
ALTER and UPDATE
Using the CARSHOWROOM database given in the chapter, write the SQL queries for the following:
- Add a new column Discount in the INVENTORY table.
- Set appropriate discount values for all cars keeping in mind the following:
(i) No discount is available on the LXI model.
(ii) VXI model gives a 10 percent discount.
(iii) A 12 percent discount is given on cars other than the LXI model and VXI model. - Display the name of the costliest car with the fuel type “Petrol”.
- Calculate the average discount and total discount available on Baleno cars.
- List the total number of cars having no discount.
______ command is used to remove the primary key from a table in SQL.
Which of the following commands will delete the table from the MYSQL database?
To establish a connection between Python and SQL databases, connect() is used. Which of the following arguments may not necessarily be given while calling connect()?
Write the command to view all tables in a database.
The code given below reads the following record from the table named student and displays only those records that have marks greater than 75:
- RollNo - integer
- Name - string
- Clas - integer
- Marks - integer
Note the following to establish connectivity between Python and MYSQL:
- Username is root.
- The password is the tiger.
- The table exists in an MYSQL database named school.
Write the following missing statements to complete the code:
Statement 1 - to form the cursor object
Statement 2 - to execute the query that extracts records of those students whose marks are greater than 75.
Statement 3 - to read the complete result of the query (records whose marks are greater than 75) into the object named data, from the table student in the database.
import mysql.connector as mysql
def sql_data():
con1=mysql.connect(host="localhost",user="root",password="tiger", database="school")
mycursor=_______________ #Statement 1
print("Students with marks greater than 75 are :")
_________________________ #Statement 2
data=__________________ #Statement 3
for i in data:
print(i)
print()Navdeep creates a table RESULT with a set of records to maintain the marks secured by students in Sem1, Sem2, Sem3, and their divisions. After the creation of the table, he entered data of 7 students in the table.
| ROLL_NO | SNAME | SEM1 | SEM2 | SEM3 | DIVISION |
| 101 | KARAN | 366 | 410 | 402 | I |
| 102 | NAMAN | 300 | 350 | 325 | I |
| 103 | ISHA | 400 | 410 | 415 | I |
| 104 | RENU | 350 | 357 | 415 | I |
| 105 | ARPIT | 100 | 75 | 178 | IV |
| 106 | SABINA | 100 | 205 | 217 | II |
| 107 | NEELAM | 470 | 450 | 471 | I |
Based on the data given above answer the following questions:
- Identify the most appropriate column, which can be considered as the Primary key.
- If two columns are added and 2 rows are deleted from the table result, what will be the new degree and cardinality of the above table?
- Write the statements to:
a. Insert the following record into the table
Roll No - 108, Name - Aadit, Sem1- 470, Sem2 - 444, Sem3 - 475, Div - I.
b. Increase the SEM2 marks of the students 3% whose name begins with ‘N’.
OR
Write the statements to:
a. Delete the record of students securing IV division.
b. Add a column REMARKS in the table with datatype as varchar with 50 characters.
Write the command to view all databases.
Name any two DDL commands.
