HCatalog related..
The HCatLoader and HCatStorer APIs are used with Pig scripts to read and write data in HCatalog-managed tables. No HCatalog-specific setup is required for these interfaces. HCatloader HCatLoader is used with Pig scripts to…
The HCatInputFormat and HCatOutputFormat interfaces are used to read data from HDFS and after processing, write the resultant data into HDFS using MapReduce job. Let us elaborate the Input and Output format interfaces. HCatInputFormat…
HCatalog contains a data transfer API for parallel input and output without using MapReduce. This API uses a basic storage abstraction of tables and rows to read data from Hadoop…
Creating an Index An Index is nothing but a pointer on a particular column of a table. Creating an index means creating a pointer on a particular column of a…
A partition is a condition for tabular data which is used for creating a separate table or view. SHOW PARTITIONS lists all the existing partitions for a given base table.…
You often want to list all the tables in a database or list all the columns in a table. Obviously, every database has its own syntax to list the tables…
We will describes how to create and manage a view in HCatalog. Database views are created using the CREATE VIEW statement. Views can be created from a single table, multiple tables, or another view.…
In this we will explains how to alter the attributes of a table such as changing its table name, changing column names, adding columns, and deleting or replacing columns. Alter…
In this we will explains how to create a table and how to insert data into it. The conventions of creating a table in HCatalog is quite similar to creating…
HCatalog Command Line Interface (CLI) can be invoked from the command $HIVE_HOME/HCatalog/bin/hcat where $HIVE_HOME is the home directory of Hive. hcat is a command used to initialize the HCatalog server. Use the following command…