Database Reference
In-Depth Information
Launching the Impala shell
Now, we will launch the Impala shell and verify if the
autos
database is created and
both
automobiles
and
automakers
are created or not. Let's launch the Impala
shell first as follows:
$impala-shell
Once the Impala shell is started, I have used the
autos
database first and verified
our steps from the preceding script.
Database and table specific commands
Now, we will use some database and table commands to verify the execution of the
script in the previous sections. Once we see that the database is created and data is
loaded, we can push queries from the Impala shell against our example database as
follows:
[Hadoop.testdomain:21000] > USE autos;
[Hadoop.testdomain:21000] > SHOW tables;
Query finished, fetching results ...
+-------------+
| name |
+-------------+
| automakers |
| automobiles |
+-------------+
Returned 2 row(s) in 0.11s
In the preceding code, we are first using the
autos
databases and then listing all the
tables within this selected database.
In the next step, we will understand each table's schema using the
describe
com-
mand as shown in the following two examples. The first example is as follows:
