- The YARS-PG serialization was designed to be simple, extensible and platform independent, and to support all - the - features provided by the current database systems based on the property graph data model. -
-- This is very early draft of YARS-PG specification based on YARS-PG 4.0. -
-This document defines YARS-PG, a serialization for property graphs.
- -The YARS-PG serialization supports all the features allowed by the current database systems based on the - property - graph data model, and can be adapted to work with various visualization software, database-driven systems - and - other graph-oriented tools.
-An one-line comment allows to place additional information in the file that is not taken into - account during its processing.
- -A prefix declaration associates a prefix label with an IRI.
- -A document metadata declaration associates metadata key (IRI or QName) with metadata value - (string or IRI).
- -A node declaration begins with the node identifier, followed by an optional list of node labels and - optional node properties, optional list of graph names and optional annotation list.
- -An edge declaration begins with the source node identifier, followed by relationship
- identifier
- (optional), a label, a set of properties (optional), target node identifier, optional list of graph
- names and optional annotation list. Edge can be
- directed (->) or undirected (-).
p:v, where p is the property label
- and v the property value. A
- property value could be atomic (e.g. String, Integer, Float, Null, Boolean) or complex (e.g. a list of
- atomic values).
-
- k:v, where k is the key (that
- can be a string, QName or IRI) and v the value of attribute (that can be QName or IRI for QName
- and IRI key and string for string key).
-
- A Named Property Graph declaration is represented as a list of graphs names.
-Graph names can be added to node, edge and node schema declarations.
- -An YARS-PG schemas may be used to determine the expected structure of a YARS-PG document.
-A node schema declaration begins with optional list of node labels, followed by optional properties of - the node with its value type, optional list of graph names and optional annotation list.
- -An edge schema declaration begins with the node label, followed by an edge label,
- a set of properties (optional) and target node label. Edge schema can be
- directed (->) or undirected (-).
YARS-PG supports several primitive and complex datatypes including String,
- Integer, Date and List. Datatypes can be used to declare the
- type
- of expected value in schemas.
The following primitive datatypes are supported:
- Decimal, SmallInt, Integer, BigInt,
- Float, Real, Double, Bool, Null,
- String, Date, Time and DateTime.
The following complex datatypes are supported:
- Set, List and Struct.
Set disallows duplicate elements and provided
- the order of retrieval is not significant. List allows duplicate elements and provided
- the order of retrieval is significant. Struct is a collection of name/value pairs.
-
A canonical version of YARS-PG must meet the list of conditions specified below.
-U+0020 or tabs U+0009) between serialization
- elements (e.g. excluding String value),The following algorithm can be used to convert YARS-PG into a canonical form:
-U+0020 or tabs U+0009) between
- serialization elementsThe grammar of YARS-PG is written in [[ANTLR4]]. We have also prepared a preview of the grammar in - [[EBNF-NOTATION]]. -
- -A preview version of YARS-PG grammar in [[EBNF-NOTATION]] is presented below.
-| [1] | -yarspg |
-::= | --statement* - | -
| [2] | -statement |
-::= | --node -| edge -| prefix_directive -| metadata -| node_schema -| edge_schema -| section - | -
| [3] | -prefix_directive |
-::= | --pname IRI - | -
| [4] | -pname |
-::= | --":" ALNUM_PLUS ":" - | -
| [5] | -pn_local |
-::= | --ALNUM_PLUS - | -
| [6] | -metadata |
-::= | --"-" ((pn_local pname) | (IRI ":")) (STRING | IRI) - | -
| [7] | -graph_name |
-::= | --STRING - | -
| [8] | -annotation |
-::= | --string_annotation | rdf_annotation - | -
| [9] | -string_annotation |
-::= | --STRING ":" STRING - | -
| [10] | -rdf_annotation |
-::= | --((pn_local pname) | (IRI ":")) (STRING | IRI) - | -
| [11] | -annotations_list |
-::= | --"+" annotation ("," annotation)* - | -
| [12] | -props_list |
-::= | --"[" prop ("," prop)* "]" - | -
| [13] | -graphs_list |
-::= | --"/" graph_name ("," graph_name)* "/" - | -
| [14] | -node |
-::= | --"<" node_id ">" ("{" node_label ("," node_label)* "}")? props_list? graphs_list? annotations_list? - | -
| [15] | -edge |
-::= | --directed | undirected - | -
| [16] | -section |
-::= | --"%" SECTION_NAME - | -
| [17] | -directed |
-::= | --"(" -node_id -")" -"-" -("<" edge_id ">")? -"{" -edge_label -"}" -props_list? -"->" -"(" -node_id -")" -graphs_list? -annotations_list? - | -
| [18] | -undirected |
-::= | --"(" -node_id -")" -"-" -("<" edge_id ">")? -"{" -edge_label -"}" -props_list? -"-" -"(" -node_id -")" -graphs_list? -annotations_list? - | -
| [19] | -node_id |
-::= | --STRING - | -
| [20] | -node_label |
-::= | --STRING - | -
| [21] | -prop |
-::= | --key ":" value - | -
| [22] | -edge_id |
-::= | --STRING - | -
| [23] | -edge_label |
-::= | --STRING - | -
| [24] | -key |
-::= | --STRING - | -
| [25] | -value |
-::= | --primitive_value | complex_value - | -
| [26] | -primitive_value |
-::= | --STRING | DATETYPE | NUMBER | BOOL | "null" - | -
| [27] | -complex_value |
-::= | --set | list | struct - | -
| [28] | -set |
-::= | --"{" -(primitive_value | set) -("," (primitive_value | set))* -"}" - | -
| [29] | -list |
-::= | --"[" -(primitive_value | list) -("," (primitive_value | list))* -"]" - | -
| [30] | -struct |
-::= | --"{" -key -":" -(primitive_value | struct) -("," key ":" (primitive_value | struct))* -"}" - | -
| [31] | -node_schema |
-::= | --"S" -("{" node_label ("," node_label)* "}")? -props_list_schema? -graphs_list? -annotations_list? - | -
| [32] | -props_list_schema |
-::= | --"[" prop_schema ("," prop_schema)* "]" - | -
| [33] | -prop_schema |
-::= | --key ":" value_schema - | -
| [34] | -value_schema |
-::= | --primitive_value_schema | complex_value_schema - | -
| [35] | -primitive_value_schema |
-::= | --"Decimal" -| "SmallInt" -| "Integer" -| "BigInt" -| "Float" -| "Real" -| "Double" -| "Bool" -| "Null" -| "String" -| "Date" -| "DateTime" -| "Time" - | -
| [36] | -complex_value_schema |
-::= | --set_schema | list_schema | struct_schema - | -
| [37] | -set_schema |
-::= | --"Set" -"(" -(primitive_value_schema | set_schema) -")" - | -
| [38] | -list_schema |
-::= | --"List" -"(" -(primitive_value_schema | list_schema) -")" - | -
| [39] | -struct_schema |
-::= | --"Struct" -"(" -(primitive_value_schema | struct_schema) -")" - | -
| [40] | -edge_schema |
-::= | --directed_schema | undirected_schema - | -
| [41] | -directed_schema |
-::= | --"S" -("(" node_label ")")? -"-" -"{" -edge_label -"}" -props_list_schema? -"->" -("(" node_label ")")? - | -
| [42] | -undirected_schema |
-::= | --"S" -("(" node_label ")")? -"-" -"{" -edge_label -"}" -props_list_schema? -"-" -("(" node_label ")")? - | -
| [43] | -SECTION_NAME |
-::= | --"METADATA" -| "NODE SCHEMAS" -| "EDGE SCHEMAS" -| "NODES" -| "EDGES" - | -
| [44] | -COMMENT |
-::= | --"#" ([^#xd#xa#xc])* - | -
| [45] | -STRING |
-::= | --STRING_LITERAL_QUOTE - | -
| [46] | -NUMBER |
-::= | --SIGN? ([0-9])+ "."? ([0-9])* - | -
| [47] | -BOOL |
-::= | --"true" | "false" - | -
| [53] | -DATETYPE |
-::= | --DATETIME | DATE | TIME - | -
| [54] | -DATE |
-::= | --[0-9] -[0-9] -[0-9] -[0-9] -"-" -[0-9] -[0-9] -"-" -[0-9] -[0-9] - | -
| [55] | -TIME |
-::= | --[0-9] -[0-9] -":" -[0-9] -[0-9] -":" -[0-9] -[0-9] -TIMEZONE? - | -
| [56] | -TIMEZONE |
-::= | --SIGN? [0-9] [0-9] ":" [0-9] [0-9] - | -
| [57] | -DATETIME |
-::= | --DATE "T" TIME - | -
| [58] | -SIGN |
-::= | --"+" | "-" - | -
| [48] | -STRING_LITERAL_QUOTE |
-::= | --'"' ([^"#xd#xa] | "'" | '"')* '"' - | -
| [49] | -ALNUM_PLUS |
-::= | --PN_CHARS_BASE ((PN_CHARS | ".")* PN_CHARS)? - | -
| [50] | -IRI |
-::= | --"<" -(PN_CHARS | "." | ":" | "/" | "\" | "#" | "@" | "%" | "&" | UCHAR)* -">" - | -
| [51] | -PN_CHARS |
-::= | --PN_CHARS_U | [-0-9#xB7#x0300-#x036F#x203F-#x2040] - | -
| [52] | -PN_CHARS_U |
-::= | --PN_CHARS_BASE | "_" - | -
| [59] | -UCHAR |
-::= | --("u" | "U" HEX HEX HEX HEX) HEX HEX HEX HEX - | -
| [60] | -PN_CHARS_BASE |
-::= | --[A-Za-z0-9#xC0-#xD6#xD8-#xF6#xF8-#x2FF#x370-#x37D#x37F-#x1FFF#x200C-#x200D#x2070-#x218F#x2C00-#x2FEF#x3001-#xD7FF#xF900-#xFDCF#xFDF0-#xFFFD] - | -
| [61] | -HEX |
-::= | --[0-9A-Fa-f] - | -
| [62] | -WS |
-::= | --([#x20#x9#xa])+ - | -
Parsers for different languages for the current grammar version will be presented later.
-