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What is default database in Hive?
By default, the database with the name “default” is the current database in the hive shell. To see the list of all databases, type “show databases”. As you can see, there are 1623 databases in Hive. To see the list of all tables, type “show tables”.
How do I create a SQLContext in Pyspark?
To create a basic SQLContext , all you need is a SparkContext. The entry point into all functionality in Spark SQL is the SQLContext class, or one of its descendants. To create a basic SQLContext , all you need is a SparkContext. JavaSparkContext sc = …; // An existing JavaSparkContext.
How will you list all databases in your schema?
To show all available databases enter the following command: SHOW DATABASES; Make sure to include the semicolon at the end.
How do I change the default database in hive?
1 Answer
- Go to the Hive service.
- Click the Configuration tab.
- Select Scope > HIVE service_name (Service-Wide)
- Select Category > Advanced.
- Deselect the Bypass Hive Metastore Server property.
- Click Save Changes to commit the changes.
- Re-deploy Hive client configurations.
What is the difference between SparkContext and SQLContext?
sparkContext is a Scala implementation entry point and JavaSparkContext is a java wrapper of sparkContext . SQLContext is entry point of SparkSQL which can be received from sparkContext . Prior to 2. x.x, RDD ,DataFrame and Data-set were three different data abstractions.
Where do I Find my database in hive?
If you wanted to check if the database already exists before creating, use IF NOT EXISTS clause. Hive by default creates a directory with a database name .db extension (for example emp.db) under its warehouse directory. By default warehouse directory located is /user/hive/warehouse on hdfs.
How does the JDBC driver support the Hive database?
With JDBC Driver’s help, the end-user can connect with the Hive database and fetch the data/records with the support of SQL Query. In the Hive, the database framework is developed by Facebook to analyze structured data or semi-structured data. The database framework supports all the regular commands like create, drop, alter, use database.
How to drop or alter database in hive?
How to Drop Database in Hive? 1 First Way: We need to drop all the tables that are present in the current database. Then we can drop the current hive… 2 Second Way: If we want to drop the hive database without dropping the current database tables. Then we can use the… More
How to check for hive table in Spark SQL?
When programming on Hive by Spark SQL, you can use following method to check whether Hive table exists. If someone is using shell script like me then my answer could be useful.