cgivre commented on a change in pull request #2129:
URL: https://github.com/apache/drill/pull/2129#discussion_r546085412
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File path: contrib/format-xml/README.md
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@@ -0,0 +1,76 @@
+# XML Format Reader
+This plugin enables Drill to read XML files without defining any kind of
schema.
+
+## Configuration
+Aside from the file extension, there is one configuration option:
+
+* `dataLevel`: XML data often contains a considerable amount of nesting which
is not necesarily useful for data analysis. This parameter allows you to set
the nesting level
+ where the data actually starts. The levels start at `1`.
+
+The default configuration is shown below:
+
+```json
+"xml": {
+ "type": "xml",
+ "extensions": [
+ "xml"
+ ],
+ "dataLevel": 2
+}
+```
+
+## Data Types
+All fields are read as strings. Nested fields are read as maps. Future
functionality could include support for lists.
+
+## Limitations: Schema Ambiguity
+XML is a challenging format to process as the structure does not give any
hints about the schema. For example, a JSON file might have the following
record:
+
+```json
+"record" : {
+ "intField:" : 1,
+ "listField" : [1, 2],
+ "otherField" : {
+ "nestedField1" : "foo",
+ "nestedField2" : "bar"
+ }
+}
+```
+
+From this data, it is clear that `listField` is a `list` and `otherField` is a
map. This same data could be represented in XML as follows:
+
+```xml
+<record>
+ <intField>1</intField>
Review comment:
Added language to README
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