delta_kernel 0.25.0

Core crate providing a Delta/Deltalake implementation focused on interoperability with a wide range of query engines.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82

// Proto mirror of `kernel/src/schema/mod.rs` 

syntax = "proto3";

package delta.kernel.schema;

// ============================================================================
// Primitive types
// ============================================================================

enum SimplePrimitiveType {
  SIMPLE_PRIMITIVE_TYPE_UNSPECIFIED = 0;
  SIMPLE_PRIMITIVE_TYPE_STRING = 1;
  SIMPLE_PRIMITIVE_TYPE_LONG = 2;
  SIMPLE_PRIMITIVE_TYPE_INTEGER = 3;
  SIMPLE_PRIMITIVE_TYPE_SHORT = 4;
  SIMPLE_PRIMITIVE_TYPE_BYTE = 5;
  SIMPLE_PRIMITIVE_TYPE_FLOAT = 6;
  SIMPLE_PRIMITIVE_TYPE_DOUBLE = 7;
  SIMPLE_PRIMITIVE_TYPE_BOOLEAN = 8;
  SIMPLE_PRIMITIVE_TYPE_BINARY = 9;
  SIMPLE_PRIMITIVE_TYPE_DATE = 10;
  SIMPLE_PRIMITIVE_TYPE_TIMESTAMP = 11;
  SIMPLE_PRIMITIVE_TYPE_TIMESTAMP_NTZ = 12;
}

// Rust uses `u8` (precision in [1,38], scale in [0,precision]); widened to uint32 because
// proto has no smaller integer type, so consumers must validate the range.
message DecimalType {
  uint32 precision = 1;
  uint32 scale = 2;
}

message PrimitiveType {
  oneof kind {
    SimplePrimitiveType simple = 1;
    DecimalType decimal = 2;
  }
}

message ArrayType {
  DataType element_type = 1;
  bool contains_null = 2;
}

message MapType {
  DataType key_type = 1;
  DataType value_type = 2;
  bool value_contains_null = 3;
}

message StructType {
  repeated StructField fields = 1;
}

message VariantType {}

message MetadataValue {
  oneof value {
    int64 number = 1;
    string string = 2;
    bool boolean = 3;
    string other_json = 4;
  }
}

message StructField {
  string name = 1;
  DataType data_type = 2;
  bool nullable = 3;
  map<string, MetadataValue> metadata = 4;
}

message DataType {
  oneof kind {
    PrimitiveType primitive = 1;
    ArrayType array = 2;
    StructType struct = 3;
    MapType map = 4;
    VariantType variant = 5;
  }
}