odps-sdk/odps-lot-proto/lot/expression.proto

import "common/types.proto";
import "common/expression.proto";
import "common/language.proto";

package apsara.odps.lot;

option java_outer_classname = "ExpressionProtos";

/*
 * 之所以不直接支持提供函数嵌套，如在值函数中引用聚合函数、在聚合函数中引用值函数、在窗口函数引用聚合函数/值函数等等是因为当用户直接构造LOT时思考方式不会这样。
 * 另外在planner内部，表达式就是这个样子
 */

message ScalarExpression
{
    optional Reference Reference = 1;
    optional Constant Constant = 2;
    optional Null Null = 3;
    optional ScalarFunction Expression = 4;
}

message ScalarFunction
{
    required string Project = 1;
    required string Name = 2;
    repeated ScalarExpression Parameters = 3;
    optional bool requireBuiltin = 4 [default = false];
}

message AggregationFunction
{
    required string Project = 1;
    required string Name = 2;
    required bool IsDistinct = 3;
    repeated ScalarExpression Parameters = 4;
    optional bool requireBuiltin = 5 [default = false];
}

message WindowFunction
{
    required string Project = 1;
    required string Name = 2;
    optional bool IsDistinct = 3;
    repeated ScalarExpression Parameters = 4;
    repeated ScalarExpression PartitionBy = 5;
    repeated group OrderBy = 6
    {
        required ScalarExpression Expression = 1;
        optional bool IsAsc = 2 [default = true]; 
    };
    optional group WindowingClause = 7
    {
        required int32 Begin = 1;
        required int32 End = 2;
    }
    optional bool requireBuiltin = 8 [default = false];
    //TODO: add other properties.
}

//UDTF,实际上聚合函数、WindowFunction都是它的特例
message TableValuedFunction
{
    required string Project = 1;
    required string Name = 2;
    repeated ScalarExpression Parameters = 3;
    repeated string OutputColumns = 4;
    repeated group Properties = 5
    {
        required string Key = 1;
        required string Value = 2;
    };
    optional bool requireBuiltin = 6 [default = false];
}

message TemporaryFunction
{
    required string Name = 1;
    repeated group Resources = 2
    {
        required string Project = 1;
        required string ResourceName = 2;
    };
    required string ClassName = 3;
    required Language Language = 4;
}