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What are the key constraints available in Hive?

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What are the key constraints available in Hive?

Hive currently let users declare the following constraints:

  • PRIMARY KEY.
  • FOREIGN KEY.
  • UNIQUE.
  • NOT NULL.

What is a meta store in Hive?

Hive metastore (HMS) is a service that stores metadata related to Apache Hive and other services, in a backend RDBMS, such as MySQL or PostgreSQL. All connections are routed to a single RDBMS service at any given time. HMS talks to the NameNode over thrift and functions as a client to HDFS.

What is a Hive catalog?

The Hive catalog serves two purposes: It is a persistent storage for pure Flink metadata. It is an interface for reading and writing existing Hive tables.

What are the modes of Hive?

Hive can operate in two modes depending on the size of data nodes in Hadoop. These modes are, Local mode. Map reduce mode.

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What is primary key in hive?

Constraints can make data predictable and easy to locate. Hive enforces constraints as follows: Ensures a value exists, which is useful in offloading data from a data warehouse. PRIMARY KEY. Identifies each row in a table using a unique identifier.

Which of the following is the key components of hive architecture?

The major components of Hive and its interaction with the Hadoop is demonstrated in the figure below and all the components are described further:

  • User Interface (UI) – As the name describes User interface provide an interface between user and hive.
  • Driver –
  • Compiler –
  • Metastore –
  • Execution Engine –

What are the types of meta stores?

There are three modes for Hive Metastore deployment:

  • Embedded Metastore.
  • Local Metastore.
  • Remote Metastore.

Where is the metadata stored in Hive?

Metastore
Metastore is a repository for Hive metadata. It stores metadata for Hive tables, and you can think of this as your schema. This is located on the Apache Derby DB. Hive uses the MapReduce framework to process queries.

How many Metastores are in the hive?

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Conclusion – Hive Metastore Above we have also discussed all the three metastore modes in detail. you can also Learn the other big data technologies like Apache Hadoop, Spark, Flink etc in detail.

What are Hive services?

Hive is a data warehouse infrastructure software that can create interaction between user and HDFS. The user interfaces that Hive supports are Hive Web UI, Hive command line, and Hive HD Insight (In Windows server). Hadoop distributed file system or HBASE are the data storage techniques to store data into file system.

What are hive components?

The major components of Apache Hive are the Hive clients, Hive services, Processing framework and Resource Management, and the Distributed Storage. The user interacts with the Hive through the user interface by submitting Hive queries. The driver passes the Hive query to the compiler.

What are the different modes of metastore deployment in hive?

There are three modes for Hive Metastore deployment: Let’s now discuss the above three Hive Metastore deployment modes one by one- i. Embedded Metastore In Hive by default, metastore service runs in the same JVM as the Hive service. It uses embedded derby database stored on the local file system in this mode.

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What is local metastore in Apache Hive?

This configuration is called as local metastore because metastore service still runs in the same process as the Hive. But it connects to a database running in a separate process, either on the same machine or on a remote machine. Before starting Apache Hive client, add the JDBC / ODBC driver libraries to the Hive lib folder.

What is a metastore in hdhive?

Hive metastore is a component that stores all the structure information(metadata) of objects like tables and partitions in the warehouse including column and column type information, the serializers and deserializers necessary to read and write data and the corresponding HDFS files where the data is stored. Any JDBC…

What is local metastore in JVM?

We can achieve by using any JDBC compliant like MySQL which runs in a separate JVM or different machines than that of the Hive service and metastore service which are running in the same JVM. This configuration is called as local metastore because metastore service still runs in the same process as the Hive.