How do I change the delimiter in hive?

How do I change the delimiter in hive?

Field delimiter can be assigned or changed in those Hive statements.

1. CREATE statement with LazySimpleSerDe interface.
2. CREATE statement with OpenCSVSerde interface.
3. ALTER statement with LazySimpleSerDe interface.
4. ALTER statement with OpenCSVSerde interface.

How do I change table properties in hive?

Changing Hive table properties

1. Select the table you want to change and click View. The default Columns tab shows the table’s columns.
2. Click the Properties tab.
3. In the Table Parameters section, locate the skipAutoProvisioning property and (if it exists) verify that its value is set to “true”.

Can we alter table in hive?

Hive provides us the functionality to perform Alteration on the Tables and Databases. ALTER TABLE command can be used to perform alterations on the tables. We can perform multiple operations with table schema like renaming the table name, add the column, change or replace the column name, etc.

What is Serdeproperties?

Use ROW FORMAT SERDE to explicitly specify the type of SerDe that Athena should use when it reads and writes data to the table. The properties specified by WITH SERDEPROPERTIES correspond to the separate statements (like FIELDS TERMINATED BY ) in the ROW FORMAT DELIMITED example.

How do you find the delimiter of a Hive table?

Try running a “show create table” command and it will show you the delimiter. When you execute the describe extended your_table_name command you will get this info in the last part (Detailed Table Information) – just search for field. delim.

What is Ctrl a delimiter?

it is a delimiter just like comma or pipe symbol(|) .. the ascii form for ctrl A is ‘/u0001’

What can be altered using alter command?

alter command is used for altering the table structure, such as,

• to add a column to existing table.
• to rename any existing column.
• to change datatype of any column or to modify its size.
• to drop a column from the table.

How do I set transaction properties in Hive?

Conclusion

1. Enable ACID Transaction Manager (DbTxnManager) on hive session.
2. Enable Concurrency.
3. Create Table by enabling transactional (TBLPROPERTIES (‘transactional’=’true’))
4. Create Table with ORC storage type.
5. Insert data into a table using INSERT INTO.
6. Finally, Run UPDATE and DELETE HiveQL queries on the table.

Can we alter external table in Hive?

You must own the external table to use ALTER EXTERNAL TABLE . To change the schema of an external table, you must also have CREATE privilege on the new schema.

What is ObjectInspector in Hive?

Hive uses ObjectInspector to analyze the internal structure of the row object and also the structure of the individual columns. ObjectInspector provides a uniform way to access complex objects that can be stored in multiple formats in the memory, including: Instance of a Java class (Thrift or native Java)

What is SerDe and explain how does it work?

SerDe is short for Serializer/Deserializer. The interface handles both serialization and deserialization and also interpreting the results of serialization as individual fields for processing. A SerDe allows Hive to read in data from a table, and write it back out to HDFS in any custom format.

What is the default field delimiter for Hive tables?

‘\001
1 Answer. The default delimiter ‘\001’ if you havn’t set when create a hivetable .

What does serde stand for in hive ALTER TABLE?

SerDe stands for serialization and deserailization. This basically tells how we should read and write the data. Using this you can replace a SerDe property or can add a new one. In the below example we lets set the SerDe to OpenCSVSerde. Using this you can add or modify table properties.

How to alter the table name in hive?

ALTER TABLE table_name SET FILEFORMAT file_type; Hive supports various file formats like CSV, TEXT, ORC, PARQUET etc. We can change the file formats using the SET FILEFORMAT statement. Our table new_tbl stores the data in Text format, lets change it to Parquet.

When to use alter table set in AWS?

ALTER TABLE SET command is used for setting the table properties. If a particular property was already set, this overrides the old value with the new one. ALTER TABLE UNSET is used to drop the table property.