GitHub user dongjoon-hyun opened a pull request:
https://github.com/apache/spark/pull/15664
[SPARK-18123][SQL] Use db column names instead of RDD column ones during
JDBC Writing
## What changes were proposed in this pull request?
Apache Spark supports the following cases **by quoting RDD column names**
while saving through JDBC.
* Allow reserved keyword as a column name, e.g., 'order'.
* Allow mixed-case colume names like the following, e.g., `[a: int, A:
int]`.
```scala
scala> val df = sql("select 1 a, 1 A")
df: org.apache.spark.sql.DataFrame = [a: int, A: int]
scala> val option = Map("url" -> "jdbc:postgresql:postgres", "dbtable" ->
"mixed", "user" -> "postgres", "password" -> "test")
scala> df.write.mode("overwrite").format("jdbc").options(option).save()
scala> df.write.mode("append").format("jdbc").options(option).save()
```
This PR aims to use database column names instead of RDD column ones in
order to support the following additionally.
Note that this case succeeds with `MySQL`, but fails on `Postgres`/`Oracle`
before.
```scala
val df1 = sql("select 1 a")
val df2 = sql("select 1 A")
...
df1.write.mode("overwrite").format("jdbc").options(option).save()
df2.write.mode("append").format("jdbc").options(option).save()
```
## How was this patch tested?
Pass the Jenkins test with a new testcase.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/dongjoon-hyun/spark SPARK-18123
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/15664.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #15664
----
commit 9558f96eb8d66ed89b2b507e81a285f710c82262
Author: Dongjoon Hyun <dongj...@apache.org>
Date: 2016-10-27T21:30:58Z
[SPARK-18123][SQL] Use database column names instead of RDD schema column
names
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