protected override DbCommand BuidUpdateCommand(SqlUpdateCommand updateCommand)
{
NpgsqlCommand cmd = new NpgsqlCommand();
BuildQueryContext ctx = new BuildQueryContext(cmd, updateCommand);
//设置上下文
ctx.BeginBuildQuery(updateCommand);
EntityModel model = Runtime.RuntimeContext.Current.GetModelAsync <EntityModel>(updateCommand.T.ModelID).Result;
ctx.AppendFormat("Update \"{0}\" t Set ", model.GetSqlTableName(false, null));
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildUpdateSet;
for (int i = 0; i < updateCommand.UpdateItems.Count; i++)
{
BuildExpression(updateCommand.UpdateItems[i], ctx);
if (i < updateCommand.UpdateItems.Count - 1)
{
ctx.Append(",");
}
}
//构建Where
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildWhere;
if (!Expression.IsNull(updateCommand.Filter))
{
ctx.Append(" Where ");
BuildExpression(ctx.CurrentQuery.Filter, ctx);
}
//构建Join
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildJoin;
SqlQueryBase 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
//最后处理返回值
if (updateCommand.OutputItems != null)
{
ctx.CurrentQueryInfo.BuildStep = BuildQueryStep.BuildWhere; //TODO: fix this?
ctx.Append(" RETURNING ");
for (int i = 0; i < updateCommand.OutputItems.Length; i++)
{
var field = (FieldExpression)updateCommand.OutputItems[i];
ctx.AppendFormat("\"{0}\"", field.Name);
if (i != updateCommand.OutputItems.Length - 1)
{
ctx.Append(",");
}
}
}
//结束用于附加条件，注意：仅在Upsert时这样操作
ctx.EndBuildQuery(updateCommand);
return(cmd);
}
public async Task ExecCommandAsync(SqlUpdateCommand updateCommand, DbTransaction txn = null)
{
//暂不支持无条件更新，以防止误操作
if (Expressions.Expression.IsNull(updateCommand.Filter))
{
throw new NotSupportedException("Update must assign Where condition");
}
var cmd = BuidUpdateCommand(updateCommand);
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
if (updateCommand.OutputItems != null && UseReaderForOutput) //返回字段通过DbReader读取
{
try
{
using var reader = await cmd.ExecuteReaderAsync();
while (await reader.ReadAsync())
{
updateCommand.SetOutputs(new SqlRowReader(reader));
}
}
catch (Exception ex)
{
Log.Warn($"Exec sql error: {ex.Message}\n{cmd.CommandText}");
throw;
}
finally
{
if (txn == null)
{
cmd.Connection.Dispose();
}
}
}
else
{
try
{
await cmd.ExecuteNonQueryAsync();
}
catch (Exception ex)
{
Log.Warn($"Exec sql error: {ex.Message}\n{cmd.CommandText}");
throw;
}
finally
{
if (txn == null)
{
cmd.Connection.Dispose();
}
}
if (updateCommand.OutputItems != null)
{
throw new NotImplementedException(); //TODO:读取输出参数值
}
}
}