What is Hive schema?

Hive stores the schema of the Hive tables in a Hive Metastore. Metastore is used to hold all the information about the tables and partitions that are in the warehouse. By default, the metastore is run in the same process as the Hive service and the default Metastore is DerBy Database.

How do I find my Hive schema?

When using Hive, you access metadata about schemas and tables by executing statements written in HiveQL (Hive’s version of SQL) such as SHOW TABLES . When using the HCatalog Connector, you can get metadata about the tables in the Hive database through several Vertica system tables.

How do you describe a database schema?

A database schema defines how data is organized within a relational database; this is inclusive of logical constraints such as, table names, fields, data types, and the relationships between these entities.

Where is the schema of Hive table stored?

Hive data are stored in one of Hadoop compatible filesystem: S3, HDFS or other compatible filesystem. Hive metadata are stored in RDBMS like MySQL, see supported RDBMS. The location of Hive tables data in S3 or HDFS can be specified for both managed and external tables.

Is Hive schema on write?

This is called as schema on write, which means when we are writing the data at that time schema is enforced. Hive supports Schema on read, which means data is checked with the schema when any query is issued on it.

How do I list databases in Hive?

From the manual: SHOW (DATABASES|SCHEMAS) [LIKE identifier_with_wildcards]; SHOW DATABASES lists all of the databases defined in the metastore. The optional LIKE clause allows the list of databases to be filtered using a regular expression.

How do you display a database schema?

You can get a list of the schemas using an SSMS or T-SQL query. To do this in SSMS, you would connect to the SQL instance, expand the SQL database and view the schemas under the security folder. Alternatively, you could use the sys. schemas to get a list of database schemas and their respective owners.

What is the difference between schema and database?

The database is a collection of schema, records, and constraints for the tables. On the other hand, a schema contains the structure of tables, attributes, their types, constraints, and how they relate to other tables. The DDL statement is used to generate and modify the schema.

What is schema example?

A schema is an outline, diagram, or model. In computing, schemas are often used to describe the structure of different types of data. Two common examples include database and XML schemas.

What is default schema in Hive?

There is not default schema in Hive, in order to query data in hive you have to first create a table explaining the content of your data (by using create external table location ). So you basically have to tell hive the “scheme” before querying the data.

How is Hive schema on read?

Hive supports Schema on read, which means data is checked with the schema when any query is issued on it. This is similar to the HDFS Write operation, where data is written distributedly on HDFS because we cannot check huge amount of data.