protected override DbCommand BuildDeleteCommand(SqlDeleteCommand deleteCommand)
{
NpgsqlCommand cmd = new NpgsqlCommand();
BuildQueryContext ctx = new BuildQueryContext(cmd, deleteCommand);
//设置上下文
ctx.BeginBuildQuery(deleteCommand);
EntityModel m = Runtime.RuntimeContext.Current.GetModelAsync <EntityModel>(deleteCommand.T.ModelID).Result;
ctx.AppendFormat("Delete From \"{0}\" t ", m.GetSqlTableName(false, null));
//构建Where
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildWhere;
if (!Expression.IsNull(deleteCommand.Filter))
{
ctx.Append(" Where ");
BuildExpression(ctx.CurrentQuery.Filter, ctx);
}
//构建Join
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildJoin;
var q1 = (SqlQueryBase)ctx.CurrentQuery;
if (q1.HasJoins) //先处理每个手工的联接及每个手工联接相应的自动联接
{
BuildJoins(q1.Joins, ctx);
}
ctx.BuildQueryAutoJoins(q1); //再处理自动联接
ctx.EndBuildQuery(deleteCommand);
return(cmd);
}
public async Task <int> ExecCommandAsync(SqlDeleteCommand deleteCommand, DbTransaction txn = null)
{
//暂不支持无条件删除，以防止误操作
if (Expressions.Expression.IsNull(deleteCommand.Filter))
{
throw new NotSupportedException("Delete must assign Where condition");
}
var cmd = BuildDeleteCommand(deleteCommand);
cmd.Connection = txn != null ? txn.Connection : MakeConnection();
cmd.Transaction = txn;
if (txn == null)
{
await cmd.Connection.OpenAsync();
}
Log.Debug(cmd.CommandText);
//执行命令
try
{
return(await cmd.ExecuteNonQueryAsync());
}
catch (Exception ex)
{
Log.Warn($"Exec sql error: {ex.Message}\n{cmd.CommandText}");
throw;
}
finally
{
if (txn == null)
{
cmd.Connection.Dispose();
}
}
}