Getting Started with Hive

About this task

In this tutorial, you'll create a Hive table, load data from a tab-delimited text file, and run a couple of basic queries against the table. For details on setting up HiveServer2 and starting BeeLine, see Using JDBC or Beeline to Connect to HiveServer2.

NOTE If you are using HiveServer2, you will use the BeeLine CLI instead of the Hive shell, as shown below.

Take a look at the source data

About this task

First, take a look at the contents of the file using the terminal:

Procedure

Save the following data to a text file named sample-table.txt:
The sample-table.txt table columns are delimited by tabs:
```
1320352532	1001	http://www.mapr.com/doc	http://www.mapr.com	192.168.10.1
1320352533	1002	http://www.mapr.com	http://www.example.com	192.168.10.10
1320352546	1001	http://www.mapr.com	http://www.mapr.com/doc	192.168.10.1
```
If you are working on the MapR Virtual Machine, we'll be loading the file from the MapR Virtual Machine's local filesystem (not the cluster storage layer), so save the file in the MapR Home directory (for example, /home/mapr).
Make sure you are in the Home directory where you saved sample-table.txt (type cd ~ if you are not sure).
Type cat sample-table.txt to display the following output.

Results

mapr@mapr-desktop:~$ cat sample-table.txt
1320352532	1001	http://www.mapr.com/doc	http://www.mapr.com	192.168.10.1
1320352533	1002	http://www.mapr.com	http://www.example.com	192.168.10.10
1320352546	1001	http://www.mapr.com	http://www.mapr.com/doc	192.168.10.1

Notice that the file consists of only three lines, each of which contains a row of data fields separated by the TAB character. The data in the file represents a web log.

Create a table in Hive and load the source data:

Procedure

Type the following command to start the Hive shell, using tab-completion to expand the <version>:
```
/opt/mapr/hive/hive-<version>/bin/hive 
```

At the hive> prompt, type the following command to create the table:

CREATE TABLE web_log(viewTime INT, userid BIGINT, url STRING, referrer STRING, ip STRING) ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';

Type the following command to load the data from sample-table.txt into the table:
```
LOAD DATA LOCAL INPATH '/home/mapr/sample-table.txt' INTO TABLE web_log;
```

Run basic queries against the table

Procedure

Try the simplest query, one that displays all the data in the table:
```
SELECT web_log.* FROM web_log;
```
This query would be inadvisable with a large table, but with the small sample table it returns very quickly.
Try a simple SELECT to extract only data that matches a desired string:
```
SELECT web_log.* FROM web_log WHERE web_log.url LIKE '%doc';
```
This query launches a MapReduce application to filter the data.