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From Andries Engelbrecht <aengelbre...@maprtech.com>
Subject Re: Table Metadata Question
Date Mon, 05 Dec 2016 16:23:15 GMT
Query INFORMATION_SCHEMA.SCHEMATA for the Storage plugin and workspace information.

Will give you the name, type and whether it is mutable.

i.e.

0: jdbc:drill:> select * from SCHEMATA;
+---------------+---------------------+---------------+----------------+-------------+
| CATALOG_NAME  |     SCHEMA_NAME     | SCHEMA_OWNER  |      TYPE      | IS_MUTABLE  |
+---------------+---------------------+---------------+----------------+-------------+
| DRILL         | INFORMATION_SCHEMA  | <owner>       | ischema        | NO        
 |
| DRILL         | dfs.clicks          | <owner>       | file           | NO        
 |
| DRILL         | dfs.data            | <owner>       | file           | NO        
 |
| DRILL         | dfs.default         | <owner>       | file           | NO        
 |
| DRILL         | dfs.orders          | <owner>       | file           | NO        
 |
| DRILL         | dfs.orders_camp     | <owner>       | file           | NO        
 |
| DRILL         | dfs.root            | <owner>       | file           | NO        
 |
| DRILL         | dfs.tmp             | <owner>       | file           | YES       
 |
| DRILL         | dfs.twitter         | <owner>       | file           | NO        
 |
| DRILL         | dfs.views           | <owner>       | file           | YES       
 |
| DRILL         | maprdb              | <owner>       | hbase          | NO        
 |
| DRILL         | sys                 | <owner>       | system-tables  | NO        
 |
+---------------+---------------------+---------------+----------------+-------------+


--Andries


> On Dec 4, 2016, at 5:55 PM, Charles Givre <cgivre@gmail.com> wrote:
> 
> That’s exactly what I was looking for.  I’m working on an adapter for a BI tool.
 Is there a way also see what type of storage plugin is being used?
> 
>> On Dec 4, 2016, at 20:54, Aman Sinha <amansinha@apache.org> wrote:
>> 
>> Charles,
>> Drill does not have a metastore for tables, so unless you have defined a
>> view with CAST or are querying Hive tables (Hive has a metastore),  the
>> column types are determined at run-time.  Have you tried the typeof()
>> function ?
>> SELECT  typeof(column) FROM dfs.`data.json` LIMIT 1;
>> 
>> 
>> On Sun, Dec 4, 2016 at 8:47 AM, Charles Givre <cgivre@gmail.com> wrote:
>> 
>>> Hello all,
>>> I’m trying to figure out if there is some way to determine what types of
>>> columns a given data source contains.  It looks like this should exist in
>>> the INFORMATION_SCHEMA somewhere, but I’m not clear how to do it.
>>> 
>>> For instance, let’s say that I have a file called data.json.  I could
>>> execute:
>>> SELECT *
>>> FROM dfs.`data.json`
>>> LIMIT 0
>>> and get the column names, but is there some way to get at the data types
>>> for these columns?
>>> TIA,
>>> — Charles
> 


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