What is the difference between truncate and delete?

The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row. TRUNCATE TABLE removes the data by deallocating the data pages used to store the table data and records only the page deallocations in the transaction log. DELETE command is slower than TRUNCATE command.

What is difference between TRUNCATE and delete in SQL Server?

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.

Why use TRUNCATE instead of delete?

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 the difference between TRUNCATE and delete which one is faster and why?

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.

What is difference between TRUNCATE DROP and delete explain with example?

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.

Difference between DELETE, TRUNCATE AND DROP in SQL.

What is rollback in SQL?

ROLLBACK is a transactional control language in SQL. It lets a user undo those transactions that aren't saved yet in the database. One can make use of this command if they wish to undo any changes or alterations since the execution of the last COMMIT.

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 union and union all in SQL?

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 difference between DROP and delete?

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 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.

Is rollback possible in 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.

Is TRUNCATE DDL or DML?

Although TRUNCATE TABLE is similar to DELETE , it is classified as a DDL statement rather than a DML statement.

Can we rollback delete and TRUNCATE?

We can rollback a delete query but not so for truncate and drop. When I execute queries then successfully done with rollback in delete, drop & truncate. We can rollback the data in conditions of Delete, Truncate & Drop. But must be used Begin Transaction before executing query Delete, Drop & Truncate.

What is difference between TRUNCATE and DROP 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.

Why we use TRUNCATE in SQL?

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.

What is difference between SQL and MySQL?

SQL is a query programming language that manages RDBMS. MySQL is a relational database management system that uses SQL. SQL is primarily used to query and operate database systems. MySQL allows you to handle, store, modify and delete data and store data in an organized way.

What is difference between alter and update in SQL?

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.

Can we update more than one column in SQL?

We can update multiple columns by specifying multiple columns after the SET command in the UPDATE statement. The UPDATE statement is always followed by the SET command, it specifies the column where the update is required.

What is the difference between primary key and FOREIGN KEY?

A primary key generally focuses on the uniqueness of the table. It assures the value in the specific column is unique. A foreign key is generally used to build a relationship between the two tables. Table allows only one primary key.

What is the difference between primary key and unique key?

Both keys provide a guaranteed uniqueness for a column or a set of columns in a table or relation. The main difference among them is that the primary key identifies each record in the table, and the unique key prevents duplicate entries in a column except for a NULL value.

What is faster join or UNION?

Union will be faster, as it simply passes the first SELECT statement, and then parses the second SELECT statement and adds the results to the end of the output table.

What are DCL and TCL commands in SQL?

DCL is abbreviation of Data Control Language. It is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. TCL is abbreviation of Transactional Control Language. It is used to manage different transactions occurring within a database.

What is the difference between DBMS and database?

A database is a collection of connected information about people, locations, or things. A database management system (DBMS) is a collection of programs that allow you to create, manage, and operate a database.

What is 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.

What is Save Point in SQL?

A SAVEPOINT is a point in a transaction when you can roll the transaction back to a certain point without rolling back the entire transaction. The syntax for a SAVEPOINT command is as shown below. SAVEPOINT SAVEPOINT_NAME; This command serves only in the creation of a SAVEPOINT among all the transactional statements.