We will see how to create a table in Hive using SEQUENCEFILE format and how to import data into the table.
CREATE TABLE Employee( ID BIGINT, NAME STRING, AGE INT, SALARY BIGINT ) COMMENT 'This is Employee table stored as sequencefile' ROW FORMAT DELIMITED FIELDS TERMINATED BY ',' STORED AS SEQUENCEFILE;
Load data into the table from Sequencefiles
To load data in the table directly from files, we need to have the input files as SEQUENCEFILEs.
Input File :-
On our HDFS, we have a sequencefile ‘/home/hadoop/data/employeeseq‘ containing employee data. We will load this data in our Employee table.
Load Data from file:-
#To overwrite the data in the table use - LOAD DATA INPATH '/home/hadoop/data/employeeseq' OVERWRITE INTO TABLE Employee; #To append the data in the table use - LOAD DATA INPATH '/home/hadoop/data/employeeseq' INTO TABLE Employee;
Load data into the table using a select query
To load data into the table using a select query use the following:-
#Overwrite data from result of a select query into the table INSERT OVERWRITE TABLE Employee SELECT id, name, age, salary from Employee_text; #Append data from result of a select query into the table INSERT INTO TABLE Employee SELECT id, name, age, salary from Employee_text;
Load Data from Text or CSV files
If you have data in text or csv format, then first load that data in a temporary table, which stores data in TEXTFILE format, and then import data from the temporary table into this table using a select query.