DROP TABLE is Data Definition Language (DDL) Command which is used to delete entire table including all schema (structure and constraints) and records. DROP TABLE DELETE Delete entire schema Delete records only WHERE clause can not be used WHERE clause can be used It is DDL It is DML
INSERT INTO PendingSELECT * FROM AccountWHERE amt_outstanding > 10000;
Table constraints are validations which can be applied on a group of columns of the table. For exp – CHECK, UNIQUE etc. Column level constraints are validations which can be applied on individual columns of the tables. For exp – NOT NULL, DEFAULT etc. Table Constraints Column Constraints It appears at the end of table
What are table constraints? What are column constraints? How are these two different? Read More »
In RDBMS, to ensure that two tables are related with each other using Referential Intigrity, Primary and Foreign key relationship is used. When two tables are related using common field, the related field in primary table is declared as Primary key and hence the same related field in secondary (related) table is taken as Foreign
How is FOREIGN KEY related to PRIMARY KEY command? Read More »
PRIMARY KEY FOREIGN KEY A table can have only one Primary Key A table can have more than one Foreign Key Primary key can not have NULL values Foreign key can have NULL values Primary Key can not have duplicate values Foreign key can have duplicate values Primary key can be defined independently Foreign key
How is FOREIGN KEY commands different from PRIMARY KEY command? Read More »
The common field which is Primary key in another related table is called Foriegn key. Foriegn key is a constraint which ensures that relationship between records in related tables are valid and user can not delete or update related data accidently.We can define Foreign key in two ways- 1) Using CREATE TABLE- FOREIGN KEY <column
What is Foreign key? How do you define a Foreign key in your table? Read More »
(a) Select all the Nonmedical stream students from STUDENT1.(b) List the name of those students who are in class 12 sorted by Stipend.(c) List all student sorted by AvgMark in descending order. Ans: (a) SELECT * FROM STUDENT WHERE STREAM = “Nonmedical”; (b) SELECT NAME FROM STUDENT WHERE CLASS LIKE “12%” ORDER BY STIPEND; (c)
Write SQL commands for the following in the basis of given table STUDENT. Read More »
(a) To show all information about the swimming coaches in the club(b) To list names of all coaches with their date of appointment (DATEOFAPP0 in descending order.(c) To display a report, showing coachname, pay, age and bonus (15% of pay) of all the coaches. Ans: (a) SELECT * FROM CLUB WHERE SPORT = “Swimming”; (b)
Write SQL commands for the following on the basis of given table Club. Read More »
Write command of SQL for(i) To display the names of all the products with price more than 20000(ii) To display the names of all products by the manufacturer “Aone”(iii) To change the price data of all the products by applying 25% discount reduction.(iv) To add a new row for product with the details: “P7”, “Vibro
Write commands of SQL for(i) To display the names of all the items whose name starts with “A”(ii) To display ICODEs and INAMEs of all items, whose Brandname is Reliable or Coscore(iii) To change the Brandname to “Fit Trend India” of the item, whose ICODE as “G101”.(iv) Add a new row for new item in
