C#-等待创建数据库完成
作者:互联网
我有这样的代码:
using (var sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
using (var sqlCommand = new SqlCommand(scriptText, sqlConnection))
{
sqlCommand.ExecuteNonQuery();
}
}
我第一次调用它来创建一个数据库,然后形成一个到该数据库的连接字符串,并尝试做一些工作(“打开”工作正常,并说该连接实际上已为第二个连接打开).但是我收到“远程主机强行关闭了现有连接”,并且可以看到sql日志“找不到数据库ID9.数据库可能尚未激活或正在转换中”.因此,实际上ExecuteNonQuery在作业完成之前返回.当然,我可以对它进行垃圾邮件处理,直到情况发生变化为止,但是还有更好的方法等待数据库准备工作吗?
解决方法:
这个完整的示例对我有用.
它创建数据库,创建表,在表中放置一行.
不确定您的问题出在哪里.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
namespace GranadaCoder.PlaygroundConsole.SqlStuff
{
public class SqlPlayground
{
public static void EntryPointStuff()
{
string databaseName = "MyFirstDatabaseABC";
string connectionString = string.Empty;
string commandText = string.Empty;
int returnValue = 0;
string msg = string.Empty;
SqlConnectionStringBuilder builder = new SqlConnectionStringBuilder();
builder["Initial Catalog"] = "master";
builder["integrated Security"] = true;
builder["Server"] = @"MyMachine\MyInstance";
connectionString = builder.ConnectionString;
commandText = string.Format("IF EXISTS (Select * from sys.databases where name = N'{0}') DROP DATABASE [{0}]", databaseName);
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
commandText = string.Format("IF NOT EXISTS (Select * from sys.databases where name = N'{0}') CREATE DATABASE [{0}]", databaseName);
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
/* Change the Catalog */
builder["Initial Catalog"] = databaseName;
connectionString = builder.ConnectionString;
commandText = "if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[CodeCategory]') and OBJECTPROPERTY(id, N'IsUserTable') = 1) BEGIN DROP TABLE [dbo].[CodeCategory] END ";
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
commandText = "CREATE TABLE [dbo].[CodeCategory] ( CodeCategoryKey [smallint] not null , CodeCategoryName varchar(64) not null ) ";
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
commandText = "INSERT INTO [dbo].[CodeCategory] ( CodeCategoryKey , CodeCategoryName ) Select 1001 , 'MyFirstCodeCategory' ";
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
commandText = "Select Count(*) from [dbo].[CodeCategory]";
returnValue = RunACommand(connectionString, commandText);
msg = string.Format("'{0}', {1}", returnValue, commandText);
Console.WriteLine(msg);
}
private static int RunACommand(string connectionString, string scriptText)
{
int returnValue = 0;
using (var sqlConnection = new SqlConnection(connectionString))
{
sqlConnection.Open();
using (var sqlCommand = new SqlCommand(scriptText, sqlConnection))
{
returnValue = sqlCommand.ExecuteNonQuery();
}
sqlConnection.Close();
}
return returnValue;
}
}
}
这对我有用(无一例外):
static void Main(string[] args)
{
try
{
SqlPlayground.EntryPointStuff();
Console.WriteLine("Press Enter after deleting the database in SSMS manually with 'Close Existing Connections' checked.");
Console.ReadLine();
SqlPlayground.EntryPointStuff();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Console.WriteLine("Pressing Enter To End");
Console.ReadLine();
}
标签:database-connection,c,sql-server 来源: https://codeday.me/bug/20191122/2061763.html