：ST_AsProtobuf

Sintaksis

bytea ST_AsProtobuf(trajectory traj);

Parameter

Nilai kembali

Mengembalikan objek trajektori dalam format Protobuf.

Lihat definisi Protobuf berikut:

syntax = "proto2";
option optimize_for = LITE_RUNTIME;

message Trajectory {
  required uint32 srid = 1 [default = 4326]; // Srid
  repeated Field fields = 2; // Definisi Fields
  repeated Point points = 3; // Semua titik trajektori
  repeated Event events = 4; // Events

  message Field {
    required string name = 11; // Nama Field 
    required FieldType type = 12; // Tipe Field
    required uint32 length = 13;  // Panjang Field
    required bool nullable = 14 [default = false]; // Field Nullable
  }

  message Value {  
    required bool is_null = 21 [default = false]; // Apakah null  
    oneof value_type {      
      string string_value = 22; // nilai string
      double double_value = 23; // nilai double
      float float_value = 24; // nilai float
      sint32 int32_value = 25; // nilai int32, int8 dan int16 akan masuk dalam nilai ini
      sint64 int64_value = 26; // nilai int64
      bool bool_value = 27; // nilai bool
      uint64 timestamp_value = 28; // nilai timestamp
    }
  }

  enum FieldType {
    string_type = 31;
    double_type = 32;
    integer_type = 33;
    bool_type = 34;
    timestamp_type = 35;
  }

  message Point {
    required double x = 41; // koordinat x
    required double y = 42; // koordinat y
    optional double z = 43; // nilai z , opsional
    optional double m = 44; // nilai m, opsional
    required uint64 timestamp = 45; // timestamp

    repeated Value attributes = 46; // semua nilai atribut
  }

  message Event {
    required int32 type = 51; // tipe event
    required uint64 timestamp = 52; // timestamp
  }
}

Deskripsi

Fungsi ST_AsProtobuf digunakan untuk mentransformasi objek trajektori ke format Protobuf, yang memungkinkan pertukaran atau tampilan data secara efisien.

Contoh

SELECT ST_AsProtobuf(ST_MakeTrajectory('STPOINT'::leaftype, st_geomfromtext('LINESTRING (114 35, 115 36, 116 37)', 4326), '[2010-01-01 14:30, 2010-01-01 15:30)'::tsrange, '{"leafcount":3,"attributes":{"velocity": {"type": "integer", "length": 2,"nullable" : true,"value": [120, 130, 140]}, "accuracy": {"type": "float", "length": 4, "nullable" : false,"value": [120, 130, 140]}, "bearing": {"type": "float", "length": 8, "nullable" : false,"value": [120, 130, 140]}, "vesname": {"type": "string", "length": 20, "nullable" : true,"value": ["adsf", "sdf", "sdfff"]}, "active": {"type": "timestamp", "nullable" : false,"value": ["Fri Jan 01 14:30:00 2010", "Fri Jan 01 15:00:00 2010", "Fri Jan 01 15:30:00 2010"]}}, "events": [{"1" : "Fri Jan 01 14:30:00 2010"}, {"2" : "Fri Jan 01 15:00:00 2010"}, {"3" : "Fri Jan 01 15:30:00 2010"}]}'));
---
    st_asprotobuf
---------------------
 \x08e62112105a0876656c6f63...