how can I connect to database

问题:

I use this but I can't connect DataBase

  conn1.Open();
    using (OracleCommand crtCommand = new OracleCommand);

回答1:

To make it dynamic use this;

    string sentence = "";
    string formatprototype = "";//This will hold the string to be formatted.
    string output="";

    public void SearchString()
    {
        string pattern = @".*[ ]+?[\""]{1}(?<String>[a-zA-Z0-9_]*)[\""]{1}[ ]+?MINVALUE[ ]*(?<MinValue>[-?\d]*)[ ]*MAXVALUE[ ]*(?<MaxValue>[\d]*)[ ]+?[INCREMENT]*[ ]+?[BY]*[ ]+?(?<IncrementBy>[\d]*)[ ]+?[START]*[ ]+?[WITH]*[ ]+?(?<StartWith>[\d]*)[ ]+?[CACHE]*[ ]+?(?<Cache>[\d]*)\s+?";
        Regex regex = new Regex(pattern);
        Match match = regex.Match(sentence);
        Group @string = match.Groups[1];
        Group minvalue = match.Groups[2];
        Group maxvalue = match.Groups[3];
        Group incrementby = match.Groups[4];
        Group startswith = match.Groups[5];
        Group cache = match.Groups[6];
        formatprototype = @"CREATE SEQUENCE ""{0}"" MINVALUE {1} MAXVALUE {2} INCREMENT BY {3} START WITH {4} CACHE {5} NOORDER NOCYCLE";
        if (minvalue.Value.StartsWith("-"))
        {
            output = string.Format(formatprototype, @string, minvalue, maxvalue, incrementby, maxvalue, cache);
        }
        else if (!minvalue.Value.StartsWith("-"))
        {
            output = string.Format(formatprototype, @string, minvalue, maxvalue, incrementby, minvalue, cache);
        }
        MessageBox.Show(output);
    }

Assume that SearchString() is the function in which you are doing this stuff.And make sure to assign each string that is extracted from database,to sentence.Try it and reply if it worked or not.

回答2:

for connect to Oracle from application

     string command =  "Enter your command";  
        OracleConnection orclecon;
             orclecon = new OracleConnection(connection);
  orclecon.Open();

use this for select commands:

 DataSet ds = new DataSet();
 using (OracleDataAdapter Oda = new OracleDataAdapter(command, orclecon))
                {
                    Oda.Fill(ds);
                }

and use this for insert/update/delete commands:

//used for Oracle command (insert,update,delete) if number of rows that affected >0 return true else return false

using (OracleCommand orclcommand = new OracleCommand(command, orclecon))
                        {
                            int n = orclcommand.ExecuteNonQuery();
                            if (n > 0)
                                return true;
                            else
                                return false;
                    }
    orclecon.Close();