What if ExecuteScalar returns NULL?

What if ExecuteScalar returns NULL?

ExecuteScalar: If the first column of the first row in the result set is not found, a null reference (Nothing in Visual Basic) is returned. If the value in the database is null, the query returns DBNull.

What is the use of ExecuteScalar () method?

Use the ExecuteScalar method to retrieve a single value (for example, an aggregate value) from a database. This requires less code than using the ExecuteReader method, and then performing the operations that you need to generate the single value using the data returned by a SqlDataReader.

What does ExecuteScalar return?

The ExecuteScalar() executes SQL statements as well as Stored Procedure and returned a scalar value on first column of first row in the returned Result Set. If the Result Set contains more than one columns or rows , it will take only the value of first column of the first row, and all other values will ignore.

What is ExecuteScalar in SQL?

ExecuteScalar method is used to execute SQL Commands or storeprocedure, after executing return a single value from the database. It also returns the first column of the first row in the result set from a database.

What is SqlCommand in C#?

SqlCommand in C# allow the user to query and send the commands to the database. SQL command is specified by the SQL connection object. Two methods are used, ExecuteReader method for results of query and ExecuteNonQuery for insert, Update, and delete commands. It is the method that is best for the different commands.

What data type is returned when calling the ExecuteScalar method of a command object?

Object data type is returned when calling ExecuteScalar method of command object – ADO.NET. Q.

What is the difference between SQLCommand ExecuteNonQuery and SQLCommand ExecuteScalar methods?

ExecuteScalar() only returns the value from the first column of the first row of your query. ExecuteReader() returns an object that can iterate over the entire result set. ExecuteNonQuery() does not return data at all: only the number of rows affected by an insert, update, or delete.

What is ExecuteScalar and ExecuteNonQuery?

What is the return type of ExecuteScalar () of a command object?

ExecuteScalar() is used to retrieve a single value from database, so return type of ExecuteScalar is Object.

Why do we need SqlCommand in C#?

A SqlCommand object allows you to query and send commands to a database. It has methods that are specialized for different commands. The ExecuteReader method returns a SqlDataReader object for viewing the results of a select query. For insert, update, and delete SQL commands, you use the ExecuteNonQuery method.

Does disposing SqlCommand close connection?

Dispose(); The first command was disposed when the using block was exited. The connection was still open and good for the second command. So, disposing of the command definitely does not dispose of the connection it was using.

What is execute scalar method Mcq?

Use DataReader read () method to retrieve the rows. – ExecuteScalar: This method returns single value. Its return type is Object. If you call ExecuteScalar method with a SQL statement that returns rows of data, the query executes but returns only the first column of the first row returned by the query.