Github user gatorsmile commented on a diff in the pull request:
https://github.com/apache/spark/pull/16636#discussion_r99645731
--- Diff:
sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveDDLSuite.scala
---
@@ -79,6 +79,25 @@ class HiveDDLSuite
}
}
+ test("create a hive table without schema") {
+ import testImplicits._
+ withTempPath { tempDir =>
+ withTable("tab1", "tab2") {
+ (("a", "b") :: Nil).toDF().write.json(tempDir.getCanonicalPath)
+
+ var e = intercept[AnalysisException] { sql("CREATE TABLE tab1
USING hive") }.getMessage
+ assert(e.contains("Unable to infer the schema. The schema
specification is required to " +
+ "create the table `default`.`tab1`"))
+
+ e = intercept[AnalysisException] {
+ sql(s"CREATE TABLE tab2 location '${tempDir.getCanonicalPath}'")
--- End diff --
Based on the official Hive document about [Row Formats &
SerDe](https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-RowFormats&SerDe),
users must specify the columns of the schema for the native SerDe. For the
custom SerDe, Hive will query the SerDe to get the columns in the schema. It
does not sounds Hive has such a capability to infer the schema from the data
files.
Actually, there is two unresolved tickets for it.
https://issues.apache.org/jira/browse/HIVE-8950 and
https://issues.apache.org/jira/browse/HIVE-10593. It sounds like the Hive
community prefers to adding a new DDL syntax to get the table schema from a
Parquet file (or some other format), but it is not available in Hive yet
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