Larry McCay created KNOX-2128:
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Summary: Custom DataSource and SQL Commands for KnoxShell and
KnoxShellTable
Key: KNOX-2128
URL: https://issues.apache.org/jira/browse/KNOX-2128
Project: Apache Knox
Issue Type: Improvement
Components: KnoxShell
Reporter: Larry McCay
Assignee: Larry McCay
Fix For: 1.4.0
As described in
[KIP-14|https://cwiki.apache.org/confluence/display/KNOX/KIP-14+-+KnoxShell+Improvements+for+Tabular+Data]
, GroovyShell allows for the extension of the shell itself with custom
commands. By providing commands for the management of DataSource configuration
and use in SQL queries, we can simplify the interaction with SQL engines and
databases for JDBC-based database access in KnoxShell to make for a powerful
scripting and shell environment.
DataSource and SQL commands really go hand in hand here and will be done at the
same time.
* Datasources (:datasource|:ds) CRUD and select operations for a set of JDBC
datasources that are persisted to disk in the user home directory
* SQL (:SQL|:sql) SQL query execution with persisted SQL history per datasource
Examples:
{code}
:ds add test_ds connectStr driverClass authn_type
{code}
The above will add a new datasource to the KnoxShell environment with the name
test_ds the required connectStr, the classname of the driver to use and either
"basic" or "none" for authentication requirements.
Invoking the above will actually result in a table rendering of all the
currently configured datasources.
When there are more than one, the following command must be used to select the
datasource to use for SQL commands:
{code}
:ds select test_ds
{code}
This command selects the desired datasource by name and sets it as the select
datasource context within the environment.
If there is only one datasource in the environment, its selection is implied
and the explicit selection isn't required with the above command.
Once a datasource is selected the SQL command may be used to interact with the
datasource.
{code}
:sql assign books
{code}
The above command will present the user with a Java Swing dialog to prompt for
a SQL statement, challenge the user for authentication if required and leverage
the KnoxShellTable JDBC builder API to submit the SQL query to the selected
datasource and return the resultset in a KnoxShellTable variable in KnoxShell
environment with the name books. It will also result in the rendering of the
tablular result.
The KnoxShellTable variable called "books" may then be used directly within the
KnoxShell environment using the KnoxShellTable fluent API to select, filter,
sort and join with other tables - as desired.
{code}
:ds remove test_ds
{code}
The above command invocation will remove the configured datasource and deselect
it - if selected and persist the changes.
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