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 DELETE and DROP in database?

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 is the difference between DROP TRUNCATE and DELETE?

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.

Is DROP faster than DELETE?

Performance-wise the DROP command is quick to perform but slower than TRUNCATE because it gives rise to complications. Unlike DELETE we can't rollback the data after using the DROP command. In the DROP command, table space is freed from memory because it permanently delete table as well as all its contents.

What is schema in SQL?

In a SQL database, a schema is a list of logical structures of data. A database user owns the schema, which has the same name as the database manager. As of SQL Server 2005, a schema is an individual entity (container of objects) distinct from the user who constructs the object.

Lec-53 Difference between Delete, Drop

Can DROP be rolled back?

DROP is a DDL Command. Objects deleted using DROP are permanently lost and it cannot be rolled back. Unlike TRUNCATE which only deletes the data of the tables, the DROP command deletes the data of the table as well as removes the entire schema/structure of the table from the database.

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.

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 main 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.

What is the difference between delete from table and DROP table table commands?

Delete statement performs conditional based deletion, whereas Drop command deletes entire records in the table. Delete statement removes only the rows in the table and it preserves the table structure as same, and Drop command removes all the data in the table and the table structure.

Is DROP slower than delete?

By using this command the existence of all the rows of the table is lost. It is comparatively faster than the delete command as it deletes all the rows fastly.

What is the difference between if you DROP a table and if you delete a table?

To remove specific rows, use DELETE . To remove all rows from a large table and leave the table structure, use TRUNCATE TABLE . It's faster than DELETE . To remove an entire table, including its structure and data, use DROP TABLE .

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 DROP command explain?

The DROP statement destroys the objects like an existing database, table, index, or view. A DROP statement in SQL removes a component from a relational database management system (RDBMS). Syntax: DROP object object_name Examples: DROP TABLE table_name; table_name: Name of the table to be deleted.

What is the use of DROP in SQL?

The DROP DATABASE command is used is to delete an existing SQL database.

What are cursors in SQL?

A cursor holds the rows (one or more) returned by a SQL statement. The set of rows the cursor holds is referred to as the active set. You can name a cursor so that it could be referred to in a program to fetch and process the rows returned by the SQL statement, one at a time.

Is TRUNCATE DDL or DML?

Although TRUNCATE TABLE is similar to DELETE , it is classified as a DDL statement rather than a DML statement. It differs from DELETE in the following ways: Truncate operations drop and re-create the table, which is much faster than deleting rows one by one, particularly for large tables.

What is create view in SQL?

In SQL, a view is a virtual table based on the result-set of an SQL statement. A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database.

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 TCL in SQL?

TCL stands for Transaction Control Languages. These commands are used for maintaining consistency of the database and for the management of transactions made by the DML commands. A Transaction is a set of SQL statements that are executed on the data stored in DBMS.

What is TRUNCATE in database?

TRUNCATE TABLE removes all rows from a table, but the table structure and its columns, constraints, indexes, and so on remain. To remove the table definition in addition to its data, use the DROP TABLE statement.

Which is better delete or TRUNCATE?

Truncate removes all records and doesn't fire triggers. Truncate is faster compared to delete as it makes less use of the transaction log. Truncate is not possible when a table is referenced by a Foreign Key or tables are used in replication or with indexed views.

What is union and union all in SQL?

Union means joining two or more data sets into a single set. In SQL Server, Union is used to combine two queries into a single result set using the select statements. Union extracts all the rows that are described in the query.