sqlflow.proto

syntax = "proto3";

import "google/protobuf/any.proto";

package proto;

service SQLFlow {
    // Run executes a sql statement
    //
    // SQL statements like `SELECT ...`, `DESCRIBE ...` returns a rowset.
    // The rowset might be big. In such cases, Query returns a stream
    // of RunResponse
    //
    // SQL statements like `USE database`, `DELETE` returns only a success
    // message.
    //
    // SQL statement like `SELECT ... TRAIN/PREDICT ...` returns a stream of
    // messages which indicates the training/predicting progress
    rpc Run (Request) returns (stream Response);
}

// SQL statements to run
// e.g.
//      1. `SELECT ...`
//      2. `USE ...`, `DELETE ...`
//      3. `SELECT ... TRAIN/PREDICT ...`
message Request {
    string sql = 1;		// The SQL statement to be executed.
}

message Response {
    oneof response {
        Head head = 1;
        Row row = 2;
        Message message = 3;
    }
}

// SQL statements like `SELECT ...`, `DESCRIBE ...` returns a Head
// and a sequence of Rows
message Head {
    repeated string column_names = 1;
}
message Row {
    // Null is a special marker used in Structured Query Language to indicate
    // that a data value does not exist in the database.
    // We encoded this marker as message Null, and it is one possible type of
    // google.protobuf.Any in the field data
    message Null {}
    repeated google.protobuf.Any data = 1;
}

// SQL statements like `USE database`, `DELETE` returns only a success
// message.
//
// SQL statement like `SELECT ... TRAIN/PREDICT ...` returns a stream of
// messages which indicates the training/predicting progress
message Message {
  string message = 1;
}