rank

docs/manual-EN/1.overview/1.concepts/1.data-model.md

@@ -47,6 +47,11 @@ Edges are used to connect vertices. Each edge usually represents a relationship
 
 Properties are named-value pairs within vertices and edges. In our example graph, we have used the properties `id`, `name` and `age` on **player**, `id` and `name` on **team**, and `likeness` on _**like**_ edge.
 
+## Edge Rank
+
+Edge rank is an immutable user-assigned 64-bit signed integer. It affects the edge order of the same edge type between two vertices. The edge with a higher rank value comes first. When not specified, the default rank value is zero. The current sorting basis is "binary coding order", i.e. 0, 1, 2, ... 9223372036854775807, -9223372036854775807, -9223372036854775806, ..., -1.
+
+
 ## Schema
 
 In **Nebula Graph**, schema refers to the definition of properties (name, type, etc.). Like `MySQL`, **Nebula Graph** is a **strong typed** database. The name and data type of the properties should be determined before the data is written.

docs/manual-EN/1.overview/1.concepts/2.nGQL-overview.md

@@ -34,8 +34,8 @@
   - Each vertex can associate with multiple **tags**
 - **Edge** : A Link between two vertices
   - Each edge can be uniquely identified by a tuple **<src_vid, dst_vid, edge_type, rank>**
-  - ***Edge type (ET)*** is a human readable string, internally it will be assigned a 32-bit integer. The edge type decides the property list (schema) on the edge
-  - ***Edge rank*** is an immutable user-assigned 64-bit signed integer. It affects the edge order between two vertices. The edge with a higher rank value comes first. When not specified, the default rank value is zero.
+  - ***Edge type (ET)*** is a human readable string, internally it will be assigned a 32-bit integer. The edge type decides the property list (schema) on the edge.
+  - ***Edge rank*** is an immutable user-assigned 64-bit signed integer. It affects the edge order of the same edge type between two vertices. The edge with a higher rank value comes first. When not specified, the default rank value is zero. The current sorting basis is "binary coding order", i.e. 0, 1, 2, ... 9223372036854775807, -9223372036854775807, -9223372036854775806, ..., -1.
   - Each edge can only be of one type
 - **Path** : A _non-forked_ connection with multiple vertices and edges between them
   - The length of a path is the number of the edges on the path, which is one less than the number of vertices
@@ -159,7 +159,7 @@ The following statement inserts one or more edges
 
 <span style="color:blue">**INSERT EDGE**</span> [<span style="color:blue">**NO OVERWRITE**</span>] <edge\_type\_name> [(<prop\_list>)] <span style="color:blue">**VALUES**</span> (<edge\_value>)+
 
-edge\_value ::= <vertex\_id> -> <vertex\_id> [@ <weight\>] : <prop\_value\_list>
+edge\_value ::= <vertex\_id> -> <vertex\_id> [@ <rank\>] : <prop\_value\_list>
 
 #### Update a Vertex
 
@@ -178,7 +178,7 @@ The following statement updates a vertex
 
 The following statement updates an edge
 
-<span style="color:blue">**UPDATE EDGE**</span>  <vertex\_id> -> <vertex\_id> [@<weight\>] <span style="color:blue">**OF**</span> <edge\_type>
+<span style="color:blue">**UPDATE EDGE**</span>  <vertex\_id> -> <vertex\_id> [@<rank\>] <span style="color:blue">**OF**</span> <edge\_type>
 <span style="color:blue">**SET**</span> <update\_decl>
 [<span style="color:blue">**WHERE**</span> <conditions\>]
 [<span style="color:blue">**YIELD**</span> <field\_list>]
@@ -272,8 +272,8 @@ All property names start with a letter. There are a few system property names st
 
 ### Built-in Properties
 
-\_id : Vertex id
-\_type : Edge type
-\_src : Source ID of the edge
-\_dst : Destination ID of the edge
-\_rank : Edge rank number
+- \_id : Vertex id
+- \_type : Edge type
+- \_src : Source ID of the edge
+- \_dst : Destination ID of the edge
+- \_rank : Edge rank number

docs/manual-EN/2.query-language/4.statement-syntax/2.data-query-and-manipulation-statements/fetch-syntax.md

@@ -57,7 +57,7 @@ FETCH PROP ON <edge_type> <vid> -> <vid>[@<rank>] [, <vid> -> <vid> ...] [YIELD
 
 `<vid> -> <vid>` denotes a starting vertex to (->) an ending vertex. Multiple edges are separated by comma(,).
 
-`<rank>` specifies the edge weight of the same edge type; it's optional.
+`<rank>` specifies the edge rank of the same edge type; it's optional. If not specified, the edge ranked 0 is returned by default.
 
 `[YIELD [DISTINCT] <return_list>]` is the property list returned.
 

docs/manual-EN/2.query-language/4.statement-syntax/2.data-query-and-manipulation-statements/insert-vertex-syntax.md

@@ -15,6 +15,7 @@ INSERT VERTEX statement inserts one vertex into **Nebula Graph**.
 
 * `tag_name` denotes the `tag` (vertex type), which must be created before `INSERT VERTEX`.
 * `prop_name_list` is the property name list in the given `tag_name`.
+* `vid` is the vertex ID. The current sorting basis is "binary coding order", i.e. 0, 1, 2, ... 9223372036854775807, -9223372036854775807, -9223372036854775806, ..., -1. `vid` supports specifying ID manually or using hash to generate.
 * `prop_value_list` must provide the value list according to the `prop_name_list`. If no value matches the type, an error will be returned.
 
 ## Examples

docs/manual-EN/2.query-language/4.statement-syntax/2.data-query-and-manipulation-statements/where-syntax.md

@@ -1,12 +1,13 @@
 # WHERE Syntax
 
-Currently, the `WHERE` statement only applies to the `GO` statement.
-Currently, the `WHERE` statement applies to the `GO` and `LOOKUP` statement. Note some `WHERE` filter conditions are not supported in the `LOOKUP` statement. Refer to the [LOOKUP Doc](lookup-syntax.md) for details.
+The `WHERE` clause allows you to specify a search condition for the data returned by a query. The following shows the syntax of the WHERE clause:
 
 ```ngql
 WHERE <expression> [ AND | OR <expression> ...])
 ```
 
+Currently, the `WHERE` statement applies to the `GO` and `LOOKUP` statement. Note some `WHERE` filter conditions are not supported in the `LOOKUP` statement. Refer to the [LOOKUP Doc](lookup-syntax.md) for details.
+
 Usually, `WHERE` is a set of logical combination that filters vertex or edge properties.
 
 > As syntactic sugar, logic AND is represented by `AND` or `&&` and logic OR is represented by `OR` or `||`.
@@ -54,3 +55,35 @@ nebula> GO FROM 101 OVER follow WHERE 1 == 1 OR TRUE;
 | 102         |
 ---------------
 ```
+
+## Filtering Edge Rank with WHERE
+
+You can filter the edge rank with the `WHERE` clause. For example:
+
+```ngql
+nebula> CREATE SPACE test;
+nebula> USE test;
+nebula> CREATE EDGE e1(p1 int);
+nebula> CREATE TAG person(p1 int);
+nebula> INSERT VERTEX person(p1) VALUES 1:(1);
+nebula> INSERT VERTEX person(p1) VALUES 2:(2);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@0(10);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@1(11);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@2(12);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@3(13);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@4(14);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@5(15);
+nebula> INSERT EDGE e1(p1) VALUES 1->2@6(16);
+nebula> GO FROM 1 OVER e1 WHERE e1._rank>2 YIELD e1._src, e1._dst, e1._rank AS Rank, e1.p1 | ORDER BY Rank DESC;
+====================================
+| e1._src | e1._dst | Rank | e1.p1 |
+====================================
+| 1       | 2       | 6    | 16    |
+------------------------------------
+| 1       | 2       | 5    | 15    |
+------------------------------------
+| 1       | 2       | 4    | 14    |
+------------------------------------
+| 1       | 2       | 3    | 13    |
+------------------------------------
+```