What is the return value of executenonquery?
Although the ExecuteNonQuery returns no rows, any output parameters or return values mapped to parameters are populated with data. For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command.
When should I use executenonquery in SQL?
Whenever you want to execute an SQL statement that shouldn't return a value or a record set, the ExecuteNonQuery should be used. So if you want to run an update, delete, or insert statement, you should use the ExecuteNonQuery. ExecuteNonQuery returns the number of rows affected by the statement.
What is the difference between executereader () and executenonquery ()?
Return Types of Command Methods:- 1- ExecuteNonQuery () - Integer 2-ExecuteScalar () - Object 3-ExecuteReader () - DataReader ExecuteNonQuery () : Doesn't return any data but returns affected row count. Return type is integer. ExecuteScalar Method (): It returns the value only in the first column of the first row. Return type is object.
How do I get the number of rows affected by a non-query?
SqlCommand.ExecuteNonQuery Method Executes statement against the connection and returns the number of rows affected. For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command.
What does ExecuteNonQuery return on success?
ExecuteNonQuery() Method:ExecuteNonQuery() method is used to manipulate data in database and is used for statements without results such as CREATE, INSERT, UPDATE and DELETE commands. It does not return any data but it returns number of rows affected.
What is the use of ExecuteNonQuery?
ExecuteNonQuery: Use this operation to execute any arbitrary SQL statements in SQL Server if you do not want any result set to be returned. You can use this operation to create database objects or change data in a database by executing UPDATE, INSERT, or DELETE statements.
Why does ExecuteNonQuery return?
The ExecuteNonQuery method returns an integer that represents the number of rows affected by the statement or stored procedure that was executed. If multiple statements are executed, the value returned is the sum of the records affected by all of the statements executed.
What is the difference between ExecuteScalar and ExecuteNonQuery?
Solution 1. 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.
Does ExecuteNonQuery close connection?
You don't actually need to close it at all if it's wrapped in a using as the call to Dispose() will automatically close the connection for you.
Can I use ExecuteNonQuery for select?
ExecuteNonQuery shouldn't be used for SELECT statements.
What does ExecuteNonQueryAsync return?
ExecuteNonQueryAsync(CancellationToken) The default implementation invokes the synchronous ExecuteNonQuery() method and returns a completed task, blocking the calling thread. The default implementation will return a cancelled task if passed an already cancelled cancellation token.
What does SqlDataReader return?
As explained earlier, the SqlDataReader returns data via a sequential stream. To read this data, you must pull data from a table row-by-row Once a row has been read, the previous row is no longer available.
What is difference between ExecuteNonQuery and Executequery?
ExecuteReader() returns an object that can iterate over the entire result set while only keeping one record in memory at a time. ExecuteNonQuery() does not return data at all: only the number of rows affected by an insert, update, or delete.
What does ExecuteScalar return?
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 does ExecuteScalar return if no rows?
if there is no result for the given condition cmd.ExecuteScalar() will retun null value and if you try to access a member of a null object which will obviously result in Object reference error.
Which is faster DataReader or DataSet?
The DataSet represents a complete set of data among the tables that include related tables, constraints, and relationships. However, this greater functionality comes with performance overhead; therefore, DataSet is slower than DataReader.
What is ExecuteNonQuery in powershell?
You can use the ExecuteNonQuery to perform catalog operations (for example, querying the structure of a database or creating database objects such as tables), or to change the data in a database without using a DataSet by executing UPDATE, INSERT, or DELETE statements.
What is ExecuteNonQuery in VB net?
Vb.NET ExecuteReader and ExecuteNonQuery ExecuteNonQuery : ExecuteNonQuery used for executing queries that does not return any data. It is used to execute the sql statements like update, insert, delete etc. ExecuteNonQuery executes the command and returns the number of rows affected.
What is difference between executeQuery and ExecuteNonQuery?
Moreover the executeQuery() is not used in . net but it is used in JAVA. ExecuteNonQuery: Executes Insert, Update, and Delete statements (DML statements) and returns the number of rows affected.
What is the use of SqlDataAdapter in C#?
The SqlDataAdapter provides this bridge by mapping Fill, which changes the data in the DataSet to match the data in the data source, and Update, which changes the data in the data source to match the data in the DataSet, using the appropriate Transact-SQL statements against the data source.
What is the return value of a table?
For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. When a trigger exists on a table being inserted or updated, the return value includes the number of rows affected by both the insert or update operation and the number of rows affected by the trigger or triggers. For all other types of statements, the return value is -1. If a rollback occurs, the return value is also -1.
Can you return a row as a value?
You can return value as row if you need to know result of operation.
What is an ExecuteNonQuery?
You can use the ExecuteNonQuery to perform catalog operations (for example, querying the structure of a database or creating database objects such as tables), or to change the data in a database without using a DataSet by executing UPDATE, INSERT, or DELETE statements.
When is SQLDbType other than XML used?
A SqlDbType other than Xml was used when Value was set to XmlReader .
Does ExecuteNonQuery return rows?
Although the ExecuteNonQuery returns no rows, any output parameters or return values mapped to parameters are populated with data.
What is the return type of ExecuteNonQuery?
ExecuteNonQuery () returns number of rows affected (ex: 2 rows updated), so return type of ExecuteNonQuery is Integer.ExecuteScalar () is used to retrieve a single value from database, so return type of ExecuteScalar is Object.
What does ExecuteNonQurey return?
ExecuteNonQurey will return an integer ExecuteScala will return an Object. ExecuteReader will return the DataReader object.
What are the methods used to run a query in ADO.NET?
I will explain purpose of these three methods with examples.ExecuteScalar () MethodExecuteScalar () method is used to retrieve a single value from database. It executes the defined query and returns the value in the first column of the first row in the selected result set and ignores all other columns and rows in the result set. It is use to get aggregate value from database, for example count or total of rows. So it works with non action queries that use aggregate functions. ExecuteScalar () method is a faster way when we compare it to other ways to retrieve single value from database. It returns a value as object and we have to cast it to appropriate type.Here is the example of ExecuteScalar () method. Use System.Data.SqlClient namespace for this example.C#public string GetCustomerName () {string query = "SELECT CustName FROM Customers WHERE CustID = 2";string connString = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True";SqlConnection conn = new SqlConnection (connString);SqlCommand cmd = new SqlCommand (query, conn);string custName = "";try {conn.Open ();custName = cmd.ExecuteScalar ().ToString ();}catch (Exception ex) {Response.Write (ex.Message);}finally {conn.Close ();}return custName; }VB.NETPublic Function GetCustomerName () As StringDim query As String = "SELECT CustName FROM Customers WHERE CustID = 2"Dim connString As String = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True"Dim conn As New SqlConnection (connString)Dim cmd As New SqlCommand (query, conn)Dim custName As String = ""Tryconn.Open ()custName = cmd.ExecuteScalar ().ToString ()Catch ex As ExceptionResponse.Write (ex.Message)Finallyconn.Close ()End TryReturn custName End FunctionExecuteScalar () method is used here to retrieve a single value that is customer name for a specific customer ID. It returns object value so we have to cast it in appropriate type “string” to assign it to variable.ExecuteNonQuery () MethodExecuteNonQuery () method is used to manipulate data in database and is used for statements without results such as CREATE, INSERT, UPDATE and DELETE commands. It does not return any data but it returns number of rows affected. If NO COUNT property is ON then it will not return number of rows affected. It will not give access to result set generated by the statement. The return value of number of rows affected is of type integer and you can get it in an integer variable. It will tell you how many rows have been affected in result of your statement. ExecuteNonQuery () method is a flexible method and we can use it input and output parameters.Here is the example of ExecuteNonQuery () method. Use System.Data.SqlClient namespace for this example.C#public int DeleteCustomer () {string query = "DELETE FROM Customers WHERE CustID = 5";string connString = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True";SqlConnection conn = new SqlConnection (connString);SqlCommand cmd = new SqlCommand (query, conn);int rowsAffected = 0;try {conn.Open ();rowsAffected = cmd.ExecuteNonQuery (); ;}catch (Exception ex) {Response.Write (ex.Message);}finally {conn.Close ();}return rowsAffected; }VB.NETPublic Function DeleteCustomer () As IntegerDim query As String = "DELETE FROM Customers WHERE CustID = 5"Dim connString As String = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True"Dim conn As New SqlConnection (connString)Dim cmd As New SqlCommand (query, conn)Dim rowsAffected As Integer = 0Tryconn.Open ()rowsAffected = cmd.ExecuteNonQuery ()Catch ex As ExceptionResponse.Write (ex.Message)Finallyconn.Close ()End TryReturn rowsAffected End FunctionExecuteNonQuery () method is used here to delete a record for specific customer from database table. This method returns number of rows affected as integer.ExecuteReader () MethodExecuteReader () method is used with SELECT command. It returns set of rows by executing query or stored procedure mentioned in the command object. When we use ExecuteReader () method, It is necessary that query returns value. It can return one or more result sets as a result of query. The returned data has the DataReader return type. ExecuteReader () method is a read-only and forward-only way of retrieving data. It means we cannot edit data in result set. ExecuteReader () is also a connected way of data retrieval. It uses SELECT statement to read through the table from first to last record in a connected way. Do not use ExecuteReader () method when you know that the result of the query is exactly one record. The better is to use ExecuteScalar () in this situation.Here is the example of ExecuteReader () method. Use System.Data.SqlClient namespace for this example.C#public void GetCustomerDetail () {string query = "SELECT * FROM Customers WHERE CustID = 2";string connString = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True";SqlConnection conn = new SqlConnection (connString);SqlCommand cmd = new SqlCommand (query, conn);string name = "";string city = "";string state = "";try {conn.Open ();SqlDataReader reader = cmd.ExecuteReader ();while (reader.Read ()) {name = reader ["CustName"].ToString ();city = reader ["City"].ToString ();state = reader ["state"].ToString ();}}catch (Exception ex) {Response.Write (ex.Message);}finally {conn.Close ();} }VB.NETPublic Sub GetCustomerDetail ()Dim query As String = "SELECT * FROM Customers WHERE CustID = 2"Dim connString As String = "Data Source=local;Initial Catalog=SampleDB;Integrated Security=True"Dim conn As New SqlConnection (connString)Dim cmd As New SqlCommand (query, conn)Dim name As String = ""Dim city As String = ""Dim state As String = ""Tryconn.Open ()Dim reader As SqlDataReader = cmd.ExecuteReader ()While reader.Read ()name = reader ("CustName").ToString ()city = reader ("City").ToString ()state = reader ("state").ToString ()End WhileCatch ex As ExceptionResponse.Write (ex.Message)Finallyconn.Close ()End Try End SubExecuteReader () method is used here to retrieve all detail about a specific customer. It can return any number of records. We have to call the Read () method to read data from result set.
What does "executereader" mean?
It means we cannot edit data in result set. ExecuteReader () is also a connected way of data retrieval. It uses SELECT statement to read through the table from first to last record in a connected way. Do not use ExecuteReader () method when you know that the result of the query is exactly one record.
What is the difference between ExecuteNonQuery and ExecuteScalar?
ExecuteNonQuery () : Doesn't return any data but returns affected row count. Return type is integer. ExecuteScalar Method (): It returns the value only in the first column of the first row. Return type is object.
What is the purpose of ExecuteScalar?
ExecuteScalar () method is a faster way when we compare it to other ways to retrieve single value from database.
Which method returns first column of first row in the form of Object?
ExecuteScalar () Method mainly return First Column of First Row in the form of Object and ExecuteNonQuery () return now of rows which are affected by DML Query
