检查数据库是否存在MSSQL C＃

Select count(*)

Select *

ExecuteScalar

ExecuteNonQuery

注意代码上的注释，它们解释了我所做的更改。

// No point of passing a bool if all you do is return it…
private bool CheckDatabase(string databaseName)
{
// You know it’s a string, use var
var connString = “Server=localhostSQLEXPRESS;Integrated Security=SSPI;database=master”;
// Note: It’s better to take the connection string from the config file.

var cmdText = "select count(*) from master.dbo.sysdatabases where name=@database";using (var sqlConnection = new SqlConnection(connString)){    using (var sqlCmd = new SqlCommand(cmdText, sqlConnection))    {        // Use parameters to protect against Sql Injection        sqlCmd.Parameters.Add("@database", System.Data.SqlDbType.NVarChar).Value = databaseName;        // Open the connection as late as possible        sqlConnection.Open();        // count(*) will always return an int, so it's safe to use Convert.ToInt32        return Convert.ToInt32( sqlCmd.ExecuteScalar()) == 1;    }}

}