DELETE COMMAND– In order to delete one or more tuples, DELETE command is used. If we want to delete the tuple for Teacher with ID=2345 the command is: DELETE FROM Teacher WHERE Teacher_ID=234; If the WHERE clause is missing then it will delete all the tuples in a table. DELETE FROM Teacher; The above command would delete all the tuple in the table Teacher. Alike UPDATE...
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December 28, 2015 evirtualguru_ajaygourOnline Computer EducationNo Comment
UPDATE COMMAND– This command is used to update the attribute values of one or more tuples in a table. For example in the Teacher table, we want to update the Dept_No of teachers teaching computer science to 123. This can be done using the following command: UPDATE Teacher SET Dept_No=123 WHERE Subject=”Computer Science”; We can also use the SELECT command in the WHERE clause of UPDATE command if we have to...
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December 28, 2015 evirtualguru_ajaygourOnline Computer EducationNo Comment
INSERT COMMAND – This command is used to insert a tuple in a relation. We must specify the name of the relation in which tuple is to be inserted and the values. The values must be in the same order as specified during the Create Table command. For example, consider the following table Teacher: CREATE TABLE Teacher ( Teacher_Namevarchar(20) NOT NULL, Teacher_IDinteger, Dept_Nointeger DEFAULT 234, Subject varchar(20) ); ...
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December 28, 2015 evirtualguru_ajaygourOnline Computer EducationNo Comment
ALTER TABLE COMMAND– This command is used to modify the base table definition. The modifications that can be done using this command are: Adding a column: Suppose we want to add a column Date_of_Birth in the Teacher table. Following command is used to add the column: ALTER TABLE Teacher ADD Date_of_Birth date; Teacher table is shown before and after the modification in the following figure: Dropping a column: A column can...
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December 28, 2015 evirtualguru_ajaygourOnline Computer EducationNo Comment
DROP TABLE COMMAND:This command is used to delete tables. For example, suppose you want to drop the Teacher table then the command would be: DROP TABLE Teacher CASCADE; Thus Teacher table would be dropped and with the CASCADE option, all the constraints that refer this table would also be automatically dropped. However if the requirement is that the table should not be dropped if it is being referenced in...
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December 28, 2015 evirtualguru_ajaygourOnline Computer EducationNo Comment
Religious Fundamentalism Religious fundamentalism is increasing in the entire world including India. It is rampant in Islamic countries like Egypt, Algeria, and Pakistan. Even China is not bereft of it. Pakistan was created on the basis of religion. Hostilities between two major communities in India is not a new thing. In recent years since the demolition of Babri Mosque feeling of mistrust has increased between Hindus and Muslims. Hindu fundamentalism...
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December 28, 2015 evirtualguru_ajaygour10th Class, 9th Class, Class 11, Class 12, English (Sr. Secondary), English 12, LanguagesNo Comment
Role of opposition party in India The role of opposition party in a democracy is very important. Parliamentary type of government operates on political parties. In India Multi-Party System exists. In the past there has been a dominance of single political party, i.e., Congress party. In recent years, opposition party has been playing decisive role in democratic polity in our country. Gradually it has increased its size and significance. Also...
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December 28, 2015 evirtualguru_ajaygour10th Class, 9th Class, Class 11, Class 12, English (Sr. Secondary), English 12, LanguagesNo Comment
The Concept of Secularism What is secularism? Secularism is Western concept. According to Western concept, secularism meant separation of state from religion. Individuals were free to practice any religion but state was neutral on religious matters. The concept developed during state and church controversy in 15th century in West. But in India, concept of secularism is different. India is a secular state. The word `secularism’ was added to our Preamble...
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December 28, 2015 evirtualguru_ajaygour10th Class, 9th Class, Class 11, Class 12, English (Sr. Secondary), English 12, LanguagesNo Comment
