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When I execute describe formatted table_name, then I get detailed description of the table table_name.
I am interested in two properties of the table as below:
field.delimserialization.format
field.delim is the field delimiter character in file between two column fields of the table.
But what is the meaning of serialization.format field of the table properties?
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Serialization and deserialization formats are popularly known as SerDes. Hive allows the framework to read or write data in a particular format. These formats parse the structured or unstructured data bytes stored in HDFS in accordance with the schema definition of Hive tables.
Serialization is the process of converting a data object—a combination of code and data represented within a region of data storage—into a series of bytes that saves the state of the object in an easily transmittable form.
A table property is a key-value pair which you can initialize when you perform a CREATE TABLE or a CREATE VIEW. You can UNSET existing or SET new or existing table properties using ALTER TABLE or ALTER TABLE. You can use table properties to tag tables with information not tracked by SQL.
Serializing the Data in HadoopInstantiate IntWritable class by wrapping an integer value in it. Instantiate ByteArrayOutputStream class. Instantiate DataOutputStream class and pass the object of ByteArrayOutputStream class to it. Serialize the integer value in IntWritable object using write() method.
Two properties of hive table:
field.delim is the field delimiter character in file between two column fields of the table.
where as serialization.format is the field delimiter character in file between two column fields of the table when the file is serialized .
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