C++/CLI Code Snippet - Check Record Exists in SQL Server Database
C++/CLI code snippet connects to SQL server and executes SQL statement to determine whether the given record exists in the database. RecordExists returns logical (True/False) using open database connection and SQL statement.
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C++/CLI Code Snippet - Check Record Exists in SQL Server Database
This .Net C++/CLI code snippet connects to SQL server and executes SQL statement to determine whether the given record exists in the database. To use this function simply provide open database connection and SQL statement. This function uses SqlClient name space to execute sql statement and return logical (True/False) result to check record exists or not in the database. Modify the exception handling section for your project requirements.
bool RecordExists(System::Data::SqlClient::SqlConnection ^%_SqlConnection, System::String ^_SQL) { System::Data::SqlClient::SqlDataReader ^_SqlDataReader = nullptr; try { // Pass the connection to a command object System::Data::SqlClient::SqlCommand ^_SqlCommand = gcnew System::Data::SqlClient::SqlCommand(_SQL, _SqlConnection); // get query results _SqlDataReader = _SqlCommand->ExecuteReader(); } catch (Exception ^_Exception) { // Error occurred while trying to execute reader // send error message to console (change below line to customize error handling) Console::WriteLine(_Exception->Message); return false; } if (_SqlDataReader != nullptr && _SqlDataReader->Read()) { // close sql reader before exit if (_SqlDataReader != nullptr) { _SqlDataReader->Close(); delete _SqlDataReader; } // record found return true; } else { // close sql reader before exit if (_SqlDataReader != nullptr) { _SqlDataReader->Close(); delete _SqlDataReader; } // record not found return false; } }
Here is a simple example showing how to use above function (RecordExists) to login to SQL server and check whether the record exists in the database.
// set temporary variable for database connection System::Data::SqlClient::SqlConnection ^_SqlConnection = gcnew System::Data::SqlClient::SqlConnection(); // assign database connection string _SqlConnection->ConnectionString = "Server=SERVERADDRESS;Database=DATABASENAME;Uid=USERID;Pwd=PASSWORD;"; // Connect to database try { _SqlConnection->Open(); } catch (Exception ^_Exception) { // Error occurred while trying to connect to database Console::WriteLine(_Exception->Message); } // Check for valid open database connection before query database if (_SqlConnection != nullptr && _SqlConnection->State == ConnectionState::Open) { if (RecordExists(_SqlConnection, "SELECT name FROM sampletable WHERE productid = 2")) { // record found in DB, lets do record found task Console::WriteLine("Record exists"); } else { // record not found in DB, lets do record not found task Console::WriteLine("Record not found"); } // close database connection _SqlConnection->Close(); }
C++/CLI Keywords Used:
- SqlDataReader
- SqlConnection
- ConnectionString
- SqlCommand
- ExecuteReader
- Exception
Code Snippet Information:
- Applies To: .Net, C++, CLI, SQL, Record Exists, SQL Server, SQL Client, Connection String, Database Connection, SQL Data Reader
- Programming Language : C++/CLI
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