What is the difference between drop table and truncate table?

In SQL, the DROP command is used to remove the whole database or table indexes, data, and more. Whereas the TRUNCATE command is used to remove all the rows from the table.

What is difference between TRUNCATE DELETE and DROP in SQL?

DROP and TRUNCATE are DDL commands, whereas DELETE is a DML command. DELETE operations can be rolled back (undone), while DROP and TRUNCATE operations cannot be rolled back.

What is the difference between DROP table and DELETE table?

DELETE is a Data Manipulation Language command, DML command and is used to remove tuples/records from a relation/table. Whereas DROP is a Data Definition Language, DDL command and is used to remove named elements of schema like relations/table, constraints or entire schema.

What are 2 differences between DELETE and TRUNCATE?

Delete and truncate both commands can be used to delete data of the table. Delete is a DML command whereas truncate is DDL command. Truncate can be used to delete the entire data of the table without maintaining the integrity of the table. On the other hand , delete statement can be used for deleting the specific data.

What is difference between DROP and TRUNCATE?

In SQL, the DROP command is used to remove the whole database or table indexes, data, and more. Whereas the TRUNCATE command is used to remove all the rows from the table.

Lec-53 Difference between Delete, Drop

What is difference between DDL and DML?

DDL stands for Data Definition Language. DML stands for Data Manipulation Language. DDL statements are used to create database, schema, constraints, users, tables etc. DML statement is used to insert, update or delete the records.

What is difference between alter and update?

ALTER Command is used to add, delete, modify the attributes of the relations (tables) in the database. UPDATE Command is used to update existing records in a database.

What is the difference between primary key and foreign key in SQL?

A primary key is used to assure the value in the particular column is unique. The foreign key provides the link between the two tables.

What is DML DDL and DCL?

These SQL commands are mainly categorized into four categories as: DDL – Data Definition Language. DQl – Data Query Language. DML – Data Manipulation Language. DCL – Data Control Language.

What is difference between DROP and delete?

DELETE command is a Data Manipulation Language command whereas, DROP is a Data Definition Language Command. The point that distinguishes DELETE and DROP command is that DELETE is used to remove tuples from a table and DROP is used to remove entire schema, table, domain or constraints from the database.

What is the difference between union and union all?

The UNION ALL command is equal to the UNION command, except that UNION ALL selects all values. The difference between Union and Union all is that Union all will not eliminate duplicate rows, instead it just pulls all rows from all tables fitting your query specifics and combines them into a table.

Can we rollback TRUNCATE?

You cannot ROLLBACK TRUNCATE

Simply, you cannot rollback a transaction if it is already committed but you can do something else to get the data back (or at least some parts of it). When you execute the TRUNCATE statement, your data is still in the MDF file.

What is the difference between TRUNCATE DROP and delete Mcq?

DELETE command is a DML statement so that it can be rolled back. DROP is used to delete the whole table, including its structure. DROP is a DDL command that lost the data permanently, and it cannot be rolled back. TRUNCATE is used to delete the whole records, but it preserves the table's schema or structure.

Why is TRUNCATE faster than DROP?

TRUNCATE is faster than DELETE , as it doesn't scan every record before removing it. TRUNCATE TABLE locks the whole table to remove data from a table; thus, this command also uses less transaction space than DELETE . Unlike DELETE , TRUNCATE does not return the number of rows deleted from the table.

Why TRUNCATE is faster?

TRUNCATE is faster than DELETE because truncate does not logs the rows that are deleted where as DELETE keeps a record of rows deleted till the transaction is committed.

Can primary key be null?

A primary key defines the set of columns that uniquely identifies rows in a table. When you create a primary key constraint, none of the columns included in the primary key can have NULL constraints; that is, they must not permit NULL values.

What is the difference between char and varchar?

Difference between CHAR and VARCHAR datatypes

In CHAR, If the length of string is less than set or fixed length then it is padded with extra memory space. In VARCHAR, If the length of string is less than set or fixed length then it will store as it is without padded with extra memory spaces.

What is the biggest difference between union and union all?

The only difference between Union and Union All is that Union extracts the rows that are being specified in the query while Union All extracts all the rows including the duplicates (repeated values) from both the queries.

What is the difference between count () and count (*) function?

As you've already learned, COUNT(*) will count all the rows in the table, including NULL values. On the other hand, COUNT(column name) will count all the rows in the specified column while excluding NULL values.

What is difference between order by and group by?

Key Differences between GROUP BY and ORDER BY

The Group By clause is used to group data based on the same value in a specific column. The ORDER BY clause, on the other hand, sorts the result and shows it in ascending or descending order. It is mandatory to use the aggregate function to use the Group By.

What is foreign key SQL?

A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table. The table with the foreign key is called the child table, and the table with the primary key is called the referenced or parent table.

What is DCL and TCL?

DCL – Data Control Language. TCL - Transaction Control Language.

What is the difference between DBMS and database?

A collection of related pieces of data, whose purpose is to solve the data management needs of an institution is called a Database. Database Management Systems (DBMS), on the other hand, are very complex software which save the data on the secondary storage devices and which are used to manipulate databases.

What is the difference between DBMS and Rdbms?

DBMS stands for Database Management System, and RDBMS is the acronym for the Relational Database Management system. In DBMS, the data is stored as a file, whereas in RDBMS, data is stored in the form of tables.