Cursor is a database object to retrieve data from a result set one row at a time, instead of the T-SQL commands that operate on all the rows in the result set at one time. We use a cursor when we need to update records in a database table in singleton fashion means row by row.
What is the use of cursor in SQL Server with example?
A SQL Server cursor is a set of T-SQL logic to loop over a predetermined number of rows one at a time. The purpose for the cursor may be to update one row at a time or perform an administrative process such as SQL Server database backups in a sequential manner.
Why do we use cursor in SQL Server?
In SQL procedures, a cursor make it possible to define a result set (a set of data rows) and perform complex logic on a row by row basis. By using the same mechanics, an SQL procedure can also define a result set and return it directly to the caller of the SQL procedure or to a client application.
What is the benefit of using cursor?
Advantages of using Cursor: Cursors can provide the first few rows before the whole result set is assembled. Without using cursors, the entire result set must be delivered before any rows are displayed by the application. So using cursor, better response time is achieved.
What is cursor in database with example?
In computer science, a database cursor is a mechanism that enables traversal over the records in a database. A cursor can be viewed as a pointer to one row in a set of rows. The cursor can only reference one row at a time, but can move to other rows of the result set as needed.
What are cursors and triggers explain their roles in SQL with examples?
The main function of the cursor is retrieval of rows from the result set one at a time (row by row). A cursor is activated and thus created in response to any SQL statement. A trigger is executed in response to a DDL statement, DML statement or any database operation.
How does a cursor work in SQL?
SQL Cursor Life Cycle A cursor is declared by defining the SQL statement. A cursor is opened for storing data retrieved from the result set. When a cursor is opened, rows can be fetched from the cursor one by one or in a block to do data manipulation. The cursor should be closed explicitly after data manipulation.
What is cursor explain types of cursor with example?
Cursor is a Temporary Memory or Temporary Work Station. It is Allocated by Database Server at the Time of Performing DML(Data Manipulation Language) operations on Table by User. Cursors are used to store Database Tables. There are 2 types of Cursors: Implicit Cursors, and Explicit Cursors.
Why cursor is slow in SQL Server?
It is running slow because you are using a cursor instead a set based update. See the post from Lowell. It will do this in a fraction of the time of this cursor.
What is cursor and why it is required?
The major function of a cursor is to retrieve data, one row at a time, from a result set, unlike the SQL commands which operate on all the rows in the result set at one time. Cursors are used when the user needs to update records in a singleton fashion or in a row by row manner, in a database table.
What is cursor explain?
1) A cursor is the position indicator on a computer display screen where a user can enter text. In an operating system with a graphical user interface (GUI), the cursor is also a visible and moving pointer that the user controls with a mouse, touch pad, or similar input device.
What is cursor in SQL Oracle?
When an SQL statement is processed, Oracle creates a memory area known as context area. A cursor is a pointer to this context area. It contains all information needed for processing the statement. A cursor is used to referred to a program to fetch and process the rows returned by the SQL statement, one at a time.
When would you use a database cursor?
You must use a cursor in the following cases:
- Statements that return more than one row of data from the database server: A SELECT statement requires a select cursor.
- An INSERT statement that sends more than one row of data to the database server requires an insert cursor.
What is the difference between cursor and while loop in SQL Server?
Cursors in sql server allow you to fetch a set of data, loop through each record, and modify the values as necessary; then, you can easily assign these values to variables and perform processing on these values. While loop also same as cursor to fetch set of data and process each row in sql server.
Which is better cursor or while loop in SQL Server?
While SQL While loop is quicker than a cursor, reason found that cursor is defined by DECLARE CURSOR. Every emphasis of the loop will be executed inside system memory and consuming required server assets.