How do I read a csv file in hive?

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How do I read a csv file in hive?

Load CSV file in hive

  1. Step 1: Sample CSV File. Create a sample CSV file named as sample_1.
  2. Step 2: Copy CSV to HDFS. Run the below commands in the shell for initial setup.
  3. Step 3: Create Hive Table and Load data. Now, you have the file in Hdfs, you just need to create an external table on top of it.
  4. Step 4: Verify data.

Does hive work with CSV files?

Use the LOAD DATA command to load the data files like CSV into Hive Managed or External table.

What is Serde in hive?

SerDe is short for Serializer/Deserializer. Hive uses the SerDe interface for IO. The interface handles both serialization and deserialization and also interpreting the results of serialization as individual fields for processing.

What is Row format Serde in hive?

SERDE is a combination of Serializer and Deserializer i.e SERIALIZER + DESERIALIZER = SERDE. SERDE is popularly used to load from sources storing data in JSON format. CREATE TABLE order_json ( order_id INT, order_date STRING, cust_id STRING, order_status STRING ) ROW FORMAT SERDE ‘org.

How do I open a CSV file in Hadoop?

2 Answers

  1. move csv file to hadoop sanbox (/home/username) using winscp or cyberduck.
  2. use -put command to move file from local location to hdfs. hdfs dfs -put /home/username/file.csv /user/data/file.csv.

How do I load a CSV file into Hive using spark?

Import CSV Files into HIVE Using Spark

  1. The first step imports functions necessary for Spark DataFrame operations: >>> from pyspark.sql import HiveContext >>> from pyspark.sql.types import * >>> from pyspark.sql import Row.
  2. The RDD can be confirmed by using the type() command: >>> type(csv_data)

How do I create a CSV file in hive?

Best way to Export Hive table to CSV file

  1. Method 1 : hive -e ‘select * from table_orc_data;’ | sed ‘s/[[:space:]]\+/,/g’ > ~/output.csv.
  2. Method 2: $ hadoop fs -cat hdfs://servername/user/hive/warehouse/databasename/table_csv_export_data/* > ~/output.csvCopy.

How import CSV into Hadoop?

How do I add SerDe to my Hive?

Following are the steps to use it:

  1. Create a file in local file system called my_table and add following data to it:
  2. Start Hive CLI.
  3. Add the HCATALOG core file that has JSON SerDe class in it.
  4. Create a table to store JSON Data.
  5. Load JSON data to this table.
  6. Query the data.

How is SerDe different from FileFormat in Hive?

Hive uses Files systems like HDFS or any other storage (FTP) to store data, data here is in the form of tables (which has rows and columns). SerDe – Serializer, Deserializer instructs hive on how to process a record (Row).

Can Hadoop read csv file?

If you want to use mapreduce you can use TextInputFormat to read line by line and parse each line in mapper’s map function. Other option is to develop (or find developed) CSV input format for reading data from file.

How do I insert a CSV file into Hive table?

Create a Hive External Table – Example

  1. Step 1: Prepare the Data File. Create a CSV file titled ‘countries.csv’: sudo nano countries.csv.
  2. Step 2: Import the File to HDFS. Create an HDFS directory.
  3. Step 3: Create an External Table.