本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# DFE 中的 Gremlin 步骤覆盖
<a name="gremlin-step-coverage-in-DFE"></a>

 Gremlin DFE 是一项实验性功能，可以通过启用实例参数或使用查询提示来使用。`Neptune#useDFE`有关更多信息，请参阅[在 Neptune DFE 查询引擎中使用 Gremlin](https://docs.amazonaws.cn//neptune/latest/userguide/gremlin-with-dfe.html)。

 以下步骤可在 Gremlin DFE 中使用。

## 路径和遍历步骤：
<a name="DFE-path-and-traversal"></a>

 [asDate ()](https://tinkerpop.apache.org/docs/current/reference/#asDate-step) [https://tinkerpop.apache.org/docs/current/reference/#order-step](https://tinkerpop.apache.org/docs/current/reference/#order-step)[project ()](https://tinkerpop.apache.org/docs/current/reference/#project-step) [、[r [ange ()](https://tinkerpop.apache.org/docs/current/reference/#range-step)、repeat [()](https://tinkerpop.apache.org/docs/current/reference/#repeat-step)[、reverse ()](https://tinkerpop.apache.org/docs/current/reference/#reverse-step)、sample ()](https://tinkerpop.apache.org/docs/current/reference/#sack-step)[、s [el](https://tinkerpop.apache.org/docs/current/reference/#select-step) ect ()](https://tinkerpop.apache.org/docs/current/reference/#sample-step)、s [ideEffect ()](https://tinkerpop.apache.org/docs/current/reference/#sideeffect-step)、sp [lit ()](https://tinkerpop.apache.org/docs/current/reference/#split-step)、[unfold ()、union ()](https://tinkerpop.apache.org/docs/current/reference/#unfold-step)](https://tinkerpop.apache.org/docs/current/reference/#union-step) 

## 聚合和收集步骤：
<a name="DFE-aggregate-and-collection"></a>

 [聚合（全局）](https://tinkerpop.apache.org/docs/current/reference/#aggregate-step)、组[合（）、计数（）](https://tinkerpop.apache.org/docs/current/reference/#combine-step)[、重复数据删除（）](https://tinkerpop.apache.org/docs/current/reference/#count-step)、[重复数据删除（本地）](https://tinkerpop.apache.org/docs/current/reference/#dedup-step)[、折叠（）、组（）、groupCoun](https://tinkerpop.apache.org/docs/current/reference/#dedup-step) [t（）](https://tinkerpop.apache.org/docs/current/reference/#fold-step)[、[groupCount](https://tinkerpop.apache.org/docs/current/reference/#groupcount-step)（）](https://tinkerpop.apache.org/docs/current/reference/#group-step)、

## 数学步骤：
<a name="DFE-mathematical"></a>

 [max()](https://tinkerpop.apache.org/docs/current/reference/#max-step)、[mean()](https://tinkerpop.apache.org/docs/current/reference/#mean-step)、[min()](https://tinkerpop.apache.org/docs/current/reference/#min-step)、[sum()](https://tinkerpop.apache.org/docs/current/reference/#sum-step) 

## 元素步骤：
<a name="DFE-element"></a>

 [otherV()](https://tinkerpop.apache.org/docs/current/reference/#otherv-step)、[elementMap()](https://tinkerpop.apache.org/docs/current/reference/#elementmap-step)、[element()](https://tinkerpop.apache.org/docs/current/reference/#element-step)、[v()](https://tinkerpop.apache.org/docs/current/reference/#graph-step)、[out()、in()、both()、outE()、inE()、bothE()、outV()、inV()、bothV()、otherV()](https://tinkerpop.apache.org/docs/current/reference/#vertex-step) 

## 属性步骤：
<a name="DFE-property"></a>

 [properties()](https://tinkerpop.apache.org/docs/current/reference/#properties-step)、[key()](https://tinkerpop.apache.org/docs/current/reference/#key-step)、[valueMap()](https://tinkerpop.apache.org/docs/current/reference/#propertymap-step)、[value()](https://tinkerpop.apache.org/docs/current/reference/#value-step) 

## 筛选步骤：
<a name="DFE-filter"></a>

 [and()](https://tinkerpop.apache.org/docs/current/reference/#and-step)、[coalesce()](https://tinkerpop.apache.org/docs/current/reference/#coalesce-step)、[coin()](https://tinkerpop.apache.org/docs/current/reference/#coin-step)、[has()](https://tinkerpop.apache.org/docs/current/reference/#has-step)、[is()](https://tinkerpop.apache.org/docs/current/reference/#is-step)、[local()](https://tinkerpop.apache.org/docs/current/reference/#local-step)、[none()](https://tinkerpop.apache.org/docs/current/reference/#none-step)、[not()](https://tinkerpop.apache.org/docs/current/reference/#not-step)、[or()](https://tinkerpop.apache.org/docs/current/reference/#or-step)、[where()](https://tinkerpop.apache.org/docs/current/reference/#where-step) 

## 字符串操作步骤：
<a name="DFE-string-manipulation"></a>

 [concat()](https://tinkerpop.apache.org/docs/current/reference/#concat-step)、[lTrim()](https://tinkerpop.apache.org/docs/current/reference/#lTrim-step)、[rTrim()](https://tinkerpop.apache.org/docs/current/reference/#rtrim-step)、[substring()](https://tinkerpop.apache.org/docs/current/reference/#substring-step)、[toLower()](https://tinkerpop.apache.org/docs/current/reference/#toLower-step)、[toUpper()](https://tinkerpop.apache.org/docs/current/reference/#toUpper-step)、[trim()](https://tinkerpop.apache.org/docs/current/reference/#trim-step) 

## 谓词：
<a name="DFE-predicates"></a>
+  [Compare：eq、neq、lt、lte、gt、gte](https://tinkerpop.apache.org/docs/current/reference/#a-note-on-predicates) 
+  [Contains：within、without](https://tinkerpop.apache.org/docs/current/reference/#a-note-on-predicates) 
+  [TextP：结尾为、包含、、、不包含 notStartingWith notEndingWith](https://tinkerpop.apache.org/docs/current/reference/#a-note-on-predicates) 
+  [P：and、or、between、outside、inside](https://tinkerpop.apache.org/docs/current/reference/#a-note-on-predicates) 

## 限制
<a name="gremlin-with-dfe-limitations"></a>

 DFE 尚不支持在重复遍历内使用限制、标签和重复数据删除。

```
// With Limit inside the repeat traversal
  g.V().has('code','AGR').repeat(out().limit(5)).until(has('code','FRA'))
  
  // With Labels inside the repeat traversal
  g.V().has('code','AGR').repeat(out().as('a')).until(has('code','FRA'))
  
  // With Dedup inside the repeat traversal
  g.V().has('code','AGR').repeat(out().dedup()).until(has('code','FRA'))
```

 尚不支持包含嵌套重复项的路径或使用分支步骤。

```
// Path with branching steps
  g.V().has('code','AGR').union(identity, outE().inV()).path().by('code')
  
  
  // With nested repeat
  g.V().has('code','AGR').repeat(out().union(identity(), out())).path().by('code')
```