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.In computer science, a database cursor is a mechanism that enables traversal over the records in a database. Cursors facilitate subsequent processing in conjunction with the traversal, such as retrieval, addition and removal of database records.A cursor in DBMS allows programmers to work with individual records rather than entire sets of data. A Cursor in DBMS is particularly useful when dealing with complex queries or when working with data that needs to be updated in real-time.
When not to use cursor in SQL : Cursors could be used in some applications for serialized operations as shown in example above, but generally they should be avoided because they bring a negative impact on performance, especially when operating on a large sets of data.
What is the advantage of cursor
Cursors allow a client application to access individual rows within a result set, rather than merely retrieve a complete set of data rows. A single connection can have multiple cursors open at the same time.
Why use cursor instead of SELECT : Cursors enable an application to retrieve and manipulate individual rows without the restriction of the select loop. Within a select loop, statements cannot be issued that access the database. Use cursors in the following situations: When a program needs to scan a table to update or delete rows.
Response time Cursors can provide the first few rows before the whole result set is assembled. If you do not use cursors, the entire result set must be delivered before any rows are displayed by your application.
Cursors provide row-by-row control in SQL Server, allowing operations that set-based commands cannot. Understand their lifecycle, types, and restrictions so that you may use them efficiently as needed, balancing their benefits against any performance drawbacks.
What is the benefit of cursor
Cursors allow a client application to access individual rows within a result set, rather than merely retrieve a complete set of data rows. A single connection can have multiple cursors open at the same time.Hence you can use it for data retrieval for example. Cursor works with the rows of the result set sequentially – row by row. A cursor can be viewed as a pointer to one row in a set of rows and can only reference one row at a time, but can move to other rows of the result set as needed.Cursors enable an application to retrieve and manipulate individual rows without the restriction of the select loop. Within a select loop, statements cannot be issued that access the database. Use cursors in the following situations: When a program needs to scan a table to update or delete rows.
Cursors allow a client application to access individual rows within a result set, rather than merely retrieve a complete set of data rows. A single connection can have multiple cursors open at the same time.
Is it good to use cursor in SQL : Cursors allow us to process data row-by-row, which can be useful when we need to perform complex calculations or transformations on the data. Cursors allow us to iterate over a result set multiple times, which can be useful when we need to perform multiple operations on the same data.
Why should you avoid cursor : Cursors are used to fetch single rows from the result set returned by a query and allow the row-by-row iteration through the result set, whereas set based processing can be much faster. Cursors can also cause transactional problems because of the run time.
When should I use a cursor
What are cursors used for Cursors are often used to highlight text or objects on the screen so that they can be selected. For example, in a word processor, the cursor can be used to select text, format it, and insert new text. Users control cursors with input devices such as mice, touchpads and trackballs.
A pointer cursor looks like a hand with the index finger extended (pointing). It was historically only used when hovering over links but is now frequently used for any clickable element, such as buttons.A cursor is a data access object that can be used to either iterate over the set of rows in a table or insert new rows into a table. Cursors have three forms: search, insert, and update. Cursors are commonly used to read existing geometries and write new geometries.