ExecuteNonQuery () return value in C # attention point analysis

The example in this article describes the ExecuteNonQuery () return value note point in C #. It has some reference value for C # database program design. Share it for everyone's reference. The specific analysis is as follows:

First, when querying a table for data, we usually use ExecuteNonQuery () and determine whether the data exists or not by judging if the value is greater than the limit. The results and I imagined very inconsistent, debugging only found that the result of the return after execution is-1, for which I do not understand, looked back to the following information, as shown below:

The SqlCommand.ExecuteNonQuery method executes Transact-SQL statements on the connection and returns the number of rows affected.

Note:

You can use ExecuteNonQuery to perform directory operations, such as querying the structure of a database or creating database objects such as tables, or by executing an UPDATE, INSERT, or DELETE statement to change data in a database without using a dataset.

Although ExecuteNonQuery does not return any rows, any output parameters or return values that are 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. For all other types of statements, the return value is-1. If a rollback occurs, the return value is also-1

After reading to understand, the original SELECT statement is not suitable for ExecuteNonQuery () method, the original is so, the method used wrong! Now deliberately write it down, I hope friends do not make a similar mistake!

public int ExecuteNonQuery ();

return value

The number of rows affected.

Realize

Idbcommand.executenonquery

Note:

You can use ExecuteNonQuery to perform directory operations such as querying the structure of a database or creating database objects such as tables, or by executing an UPDATE, INSERT, or DELETE statement to change data in a database without using a dataset.

Although ExecuteNonQuery does not return any rows, any output parameters or return values that are 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. For all other types of statements, the return value is-1.

public void Createmysqlcommand (string myexecutequery, SqlConnection myconnection) {   SqlCommand mycommand = new SqlCommand (Myexecutequery, myconnection);   MyCommand.Connection.Open ();   Mycommand.executenonquery ();   Myconnection.close ();}

It is believed that this article has certain reference value for the C # program design of everybody.

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ExecuteNonQuery () return value in C # attention point analysis

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ExecuteNonQuery () return value in C # attention point analysis