/// <summary>
/// 创建一个连接
/// <remarks>
/// the connection retrieve process is as the following procedure:
/// <list type="bullet">
/// <item>if no transaction exists, this method create and return a new DbConnection instance</item>
/// <item>if transaction exists, this method should return a cached DbConnection instance</item>
/// </list>
/// <param name="isConnectionCreator">输出参数，返回连接是否创建成功</param>
/// <param name="name">数据库连接名称</param>
/// </remarks>
/// </summary>
private DbConnection CreateConnection(string name, out bool isConnectionCreator)
{
DbConnection connection;
isConnectionCreator = false;
// non-transactional operation
GraphWithoutTransaction connections = GraphWithoutTx;
if (Transaction.Current == null)
{
connection = GetConnectionWithoutTx(name);
}
else
{
connection = OnGetConnectionWithTransaction(Transaction.Current);
}
if ((connection != null) && (connection.State != ConnectionState.Open))
{
if (string.IsNullOrEmpty(connection.ConnectionString))
{
connection.ConnectionString = DbConnectionManager.GetConnectionString(name);
}
connection.Open();
WriteTraceInfo(connection.DataSource + "." + connection.Database
+ "[" + DateTime.Now.ToString("yyyyMMdd HH:mm:ss.fff") + "]", " Open Connection ");
}
return(connection);
}
/// <summary>
/// 根据名称得到当前引用的连接
/// </summary>
/// <param name="connName">数据库连接名称</param>
/// <returns>连接对象</returns>
protected ReferenceConnection GetRefConnectionWithoutTx(string connName)
{
ReferenceConnection refConnection = null;
GraphWithoutTransaction connections = GraphWithoutTx;
lock (connections)
{
if (connections.TryGetValue(connName, out refConnection) == false)
{
DbConnection connection = DbConnectionManager.GetConnection(connName);
this.isConnectionCreator = true;
refConnection = new ReferenceConnection(connName, connection);
connections.Add(connName, refConnection);
}
else
{
refConnection.ReferenceCount++;
}
}
return(refConnection);
}
private async Task <Tuple <DbConnection, bool> > CreateConnectionAsync(string name)
{
bool isConnectionCreator = false;
// non-transactional operation
GraphWithoutTransaction connections = this.GraphWithoutTx;
DbConnection connection = GetConnection(name);
if ((connection != null) && (connection.State != ConnectionState.Open))
{
if (connection.ConnectionString.IsNullOrEmpty())
{
connection.ConnectionString = DbConnectionManager.GetConnectionString(name);
}
await OpenConnectionAsync(name, connection);
WriteTraceInfo(connection.DataSource + "." + connection.Database
+ "[" + SNTPClient.AdjustedTime.ToString("yyyyMMdd HH:mm:ss.fff") + "]", " Open Connection ");
}
return(new Tuple <DbConnection, bool>(connection, isConnectionCreator));
}
