sql - Inserting Data into Hive Table


Keywords:sql 


Question: 

I am new to hive. I have successfully setup a single node hadoop cluster for development purpose and on top of it, I have installed hive and pig.

I created a dummy table in hive:

create table foo (id int, name string);

Now, I want to insert data into this table. Can I add data just like sql one record at a time? kindly help me with an analogous command to:

insert into foo (id, name) VALUES (12,"xyz);

Also, I have a csv file which contains data in the format:

1,name1
2,name2
..
..

..


1000,name1000

How can I load this data into the dummy table?


11 Answers: 

I think the best way is:
a) Copy data into HDFS (if it is not already there)
b) Create external table over your CSV like this

CREATE EXTERNAL TABLE TableName (id int, name string)
ROW FORMAT DELIMITED   
FIELDS TERMINATED BY ',' 
LINES TERMINATED BY '\n'
STORED AS TEXTFILE
LOCATION 'place in HDFS';

c) You can start using TableName already by issuing queries to it.
d) if you want to insert data into other Hive table:

insert overwrite table finalTable select * from table name;
 

There's no direct way to insert 1 record at a time from the terminal, however, here's an easy straight forward workaround which I usually use when I want to test something:

Assuming that t is a table with at least 1 record. It doesn't matter what is the type or number of columns.

INSERT INTO TABLE foo
SELECT '12', 'xyz'
FROM t
LIMIT 1;
 

Hive apparently supports INSERT...VALUES starting in Hive 0.14.

Please see the section 'Inserting into tables from SQL' at:

 

What ever data you have inserted into one text file or log file that can put on one path in hdfs and then write a query as follows in hive

  hive>load data inpath<<specify inputpath>> into table <<tablename>>;

EXAMPLE:

hive>create table foo (id int, name string)
row format delimited
fields terminated by '\t' or '|'or ','
stored as text file;
table created..
    DATA INSERTION::
    hive>load data inpath '/home/hive/foodata.log' into table foo;
 

to insert ad-hoc value like (12,"xyz), do this:

insert into table foo select * from (select 12,"xyz")a;
 

It's a limitation of hive.

1.You cannot update data after it is inserted

2.There is no "insert into table values ... " statement

3.You can only load data using bulk load

4.There is not "delete from " command

5.You can only do bulk delete

But you still want to insert record from hive console than you can do select from statck. refer this

 

You may try this, I have developed a tool to generate hive scripts from a csv file. Following are few examples on how files are generated. Tool --

  1. Select a CSV file using Browse and set hadoop root directory ex: /user/bigdataproject/

  2. Tool Generates Hadoop script with all csv files and following is a sample of generated Hadoop script to insert csv into Hadoop

    #!/bin/bash -v
    hadoop fs -put ./AllstarFull.csv /user/bigdataproject/AllstarFull.csv hive -f ./AllstarFull.hive

    hadoop fs -put ./Appearances.csv /user/bigdataproject/Appearances.csv hive -f ./Appearances.hive

    hadoop fs -put ./AwardsManagers.csv /user/bigdataproject/AwardsManagers.csv hive -f ./AwardsManagers.hive

  3. Sample of generated Hive scripts

    CREATE DATABASE IF NOT EXISTS lahman;
    USE lahman;
    CREATE TABLE AllstarFull (playerID string,yearID string,gameNum string,gameID string,teamID string,lgID string,GP string,startingPos string) row format delimited fields terminated by ',' stored as textfile;
    LOAD DATA INPATH '/user/bigdataproject/AllstarFull.csv' OVERWRITE INTO TABLE AllstarFull;
    SELECT * FROM AllstarFull;

Thanks Vijay

 

You can use following lines of code to insert values into an already existing table. Here the table is db_name.table_name having two columns, and I am inserting 'All','done' as a row in the table.

insert into table db_name.table_name
select 'ALL','Done';

Hope this was helpful.

 

Hadoop file system does not support appending data to the existing files. Although, you can load your CSV file into HDFS and tell Hive to treat it as an external table.

 

this is supported from version hive 0.14

INSERT INTO TABLE pd_temp(dept,make,cost,id,asmb_city,asmb_ct,retail) VALUES('production','thailand',10,99202,'northcarolina','usa',20)

 

Use this -

create table dummy_table_name as select * from source_table_name;

This will create the new table with existing data available on source_table_name.