A cursor keeps track of the position in the result set, and allows you to perform multiple operations row by row against a result set, with or without returning to the original table. In other words, cursors conceptually return a result set based on tables within the databases.

What is an advantage of cursor in Oracle?

Advantages. Cursor fetches the data Row wise so Row Wise validation is possible using the cursor. It retrieves one row at a time, unlike SQL select query which selects all rows at a time. It is faster than While Loop but does have more overhead. It provides traversals over records of the database.

How does 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 the use of cursor explain 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.

What is the use of cursor in Android?

A Cursor represents the result of a query and basically points to one row of the query result. This way Android can buffer the query results efficiently; as it does not have to load all data into memory.

What is cursor exception Plsql?

In PL/SQL, a warning or error condition is called an exception. … When an error occurs, an exception is raised. That is, normal execution stops and control transfers to the exception-handling part of your PL/SQL block or subprogram. Internal exceptions are raised implicitly (automatically) by the run-time system.

What is the benefit of using cursors?

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 are the disadvantages of cursors?

• Uses more resources because Each time you fetch a row from the cursor, it results in a network roundtrip.
• There are restrictions on the SELECT statements that can be used.
• Because of the round trips, performance and speed is slow.

Is it good 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 cursor short answer?

In computer user interfaces, a cursor is an indicator used to show the current position for user interaction on a computer monitor or other display device that will respond to input from a text input or pointing device. The mouse cursor is also called a pointer, owing to its resemblance in usage to a pointing stick.

Article first time published on

How do you define cursor?

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 is cursor in SQL 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.

What is cursor and index in SQL?

In SQL, a cursor can be defined as a tool used widely to define a particular set of results. This result can be a set of data rows. A cursor is basically used to solve complex logic and works on a row by row manner. Index, on the other hand, has the main function of retrieving data from tables much quicker.

What is cursor in DBMS and its types?

A cursor is a temporary work area created in the system memory when a SQL statement is executed. A cursor contains information on a select statement and the rows of data accessed by it. … There are two types of cursors in PL/SQL : Implicit cursors. Explicit cursors.

What is the use of SQLite in Android?

SQLite Database is an open-source database provided in Android which is used to store data inside the user’s device in the form of a Text file. We can perform so many operations on this data such as adding new data, updating, reading, and deleting this data.

How can use pointer in Mobile?

1. Open the Settings app then scroll down and tap Accessibility.
2. Scroll down to the Display section and tap Large mouse cursor.
3. To enable Dwell timing, scroll down to Interaction controls and tap Dwell timing.
4. Tap Use service to set the toggle switch to On.

What is the purpose of SQLite open helper class?

SQLiteOpenHelper class is used for database creation and version management. For performing any database operation, you have to provide the implementation of onCreate() and onUpgrade() methods of SQLiteOpenHelper class.

Why cursor is bad for performance?

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.

Why do we use cursor in Db2?

In Db2, an application program uses a cursor to point to one or more rows in a set of rows that are retrieved from a table. You can also use a cursor to retrieve rows from a result set that is returned by a stored procedure. Your application program can use a cursor to retrieve rows from a table.

What is a cursor in a database?

A database cursor is an identifier associated with a group of rows. It is, in a sense, a pointer to the current row in a buffer. … Statements that return more than one row of data from the database server: A SELECT statement requires a select cursor. An EXECUTE FUNCTION statement requires a function cursor.

Where are exceptions used in PL SQL?

An error occurs during the program execution is called Exception in PL/SQL. PL/SQL facilitates programmers to catch such conditions using exception block in the program and an appropriate action is taken against the error condition. There are two type of exceptions: System-defined Exceptions.

What is true about Program_error?

What is true about PROGRAM_ERROR? A. It is raised when a SELECT INTO statement returns no rows. … It is raised when a SELECT INTO statement returns more than one row.

What is package in PL SQL?

In PL/SQL, a package is a schema object that contains definitions for a group of related functionalities. A package includes variables, constants, cursors, exceptions, procedures, functions, and subprograms. It is compiled and stored in the Oracle Database. Typically, a package has a specification and a body.

What is difference between cursor and while loop?

Loop and cursor can be utilized in a circumstance to deal with row-based processing in T-SQL. … 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.

What is the purpose of using global variables in cursors?

Global items maintain their state (for a variable, its value; for a cursor, as you are about to see, its status of open or closed and if open wherein the result set the cursor is pointing) until you explicitly change that state, your session terminates, or the package state is reset.

What is implicit cursor?

An implicit cursor has attributes that return information about the most recently run SELECT or DML statement that is not associated with a named cursor. Note: You can use cursor attributes only in procedural statements, not in SQL statements.

How view is created and dropped?

Creating Views Database views are created using the CREATE VIEW statement. Views can be created from a single table, multiple tables or another view. To create a view, a user must have the appropriate system privilege according to the specific implementation. CREATE VIEW view_name AS SELECT column1, column2…..

What is the cursor status?

An application uses the cursor status property to determine how a cancel operation has affected a cursor. CS_CUR_STATUS is a command structure property and cannot be retrieved at the connection or context levels. Cursor properties are useful to gateway applications that send cursor information to clients.

What is the cursor text?

The screen pointer that appears when text can be highlighted or edited. The text cursor is a vertical line (|). Also called a “caret,” “i-cursor” or “I-beam,” it may or may not blink. If the cursor is an arrow or hand, the text cannot be highlighted or changed.

What are the main features of a cursor?

Cursors enable manipulation of whole result sets at once. In this scenario, a cursor enables the sequential processing of rows in a result set. In SQL procedures, a cursor makes it possible to define a result set (a set of data rows) and perform complex logic on a row by row basis.

Which keyword is used to declare cursor?

To create a cursor variable, either declare a variable of the predefined type SYS_REFCURSOR or define a REF CURSOR type and then declare a variable of that type. You cannot use a cursor variable in a cursor FOR LOOP statement.