3a80f92f8f
### What changes were proposed in this pull request?
For data sources without extending `SchemaRelationProvider`, we expect users to not specify schemas when they creating tables. If the schema is input from users, an exception is issued.
Since Spark 2.1, for any data source, to avoid infer the schema every time, we store the schema in the metastore catalog. Thus, when reading a cataloged data source table, the schema could be read from metastore catalog. In this case, we also got an exception. For example,
```Scala
sql(
s"""
|CREATE TABLE relationProvierWithSchema
|USING org.apache.spark.sql.sources.SimpleScanSource
|OPTIONS (
| From '1',
| To '10'
|)
""".stripMargin)
spark.table(tableName).show()
```
```
org.apache.spark.sql.sources.SimpleScanSource does not allow user-specified schemas.;
```
This PR is to fix the above issue. When building a data source, we introduce a flag `isSchemaFromUsers` to indicate whether the schema is really input from users. If true, we issue an exception. Otherwise, we will call the `createRelation` of `RelationProvider` to generate the `BaseRelation`, in which it contains the actual schema.
### How was this patch tested?
Added a few cases.
Author: gatorsmile <gatorsmile@gmail.com>
Closes #15046 from gatorsmile/tempViewCases.
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| catalyst | ||
| core | ||
| hive | ||
| hive-thriftserver | ||
| README.md | ||
Spark SQL
This module provides support for executing relational queries expressed in either SQL or the DataFrame/Dataset API.
Spark SQL is broken up into four subprojects:
- Catalyst (sql/catalyst) - An implementation-agnostic framework for manipulating trees of relational operators and expressions.
- Execution (sql/core) - A query planner / execution engine for translating Catalyst's logical query plans into Spark RDDs. This component also includes a new public interface, SQLContext, that allows users to execute SQL or LINQ statements against existing RDDs and Parquet files.
- Hive Support (sql/hive) - Includes an extension of SQLContext called HiveContext that allows users to write queries using a subset of HiveQL and access data from a Hive Metastore using Hive SerDes. There are also wrappers that allows users to run queries that include Hive UDFs, UDAFs, and UDTFs.
- HiveServer and CLI support (sql/hive-thriftserver) - Includes support for the SQL CLI (bin/spark-sql) and a HiveServer2 (for JDBC/ODBC) compatible server.