[teiid-issues] [JBoss JIRA] (TEIID-1819) Reading multi entity data from a single data file

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-1819?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins resolved TEIID-1819.
-----------------------------------

    Resolution: Done


Added the selector argument to texttable and added the ability to specify selector/position for columns to reference parent values.  This was an easier implementation path than using the nested texttable columns approach proposed above, e.g.

with the file:

A,10-dec-2011,12345,3322,3000,222
B,1,123,Sprockets Black,30,50,1500
B,2,333,Sprockets Blue,300,5,1500

select x.* from texttable(file SELECTOR 'B' COLUMNS x string, y integer, z integer SELECTOR 'A' 3) x";
    	
would return:

["B", 1, 12345],
["B", 2, 12345]

the docs and release notes were also updated.  There is no special treatment of the header when using selectors.  Note that parent values can only be selected positionally.
                
> Reading multi entity data from a single data file
> -------------------------------------------------
>
>                 Key: TEIID-1819
>                 URL: https://issues.jboss.org/browse/TEIID-1819
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: Query Engine
>    Affects Versions: 7.6
>         Environment: Any
>            Reporter: Peter Larsen
>            Assignee: Steven Hawkins
>             Fix For: 8.0
>
>         Attachments: selector.patch
>
>
> A common problem for data files is the concept of multiple data sets inclosed in the same file. An example is a data file of accounts receivable orders. You'll export at least two logical entities: Orders and OrderLines. Each of the two entities have very different data sets; the relate (OrderLines belong to a particular Order) and there are a dynamic number of OrderLines per Order.
> A common way to differentiate is to put a special "record type" selector as the first field in each record. Ie. A and B. The load program will based on this selector apply different templates to map the columns, and it will also know that the OrderLines are associated with the Order above it and create that relation column ID in the out put.
> Example:
> ;selector=A,orderdate,ordernumber,customernumber,ordertotal,ordertax
> ;selector=B,lineno,itemno,description,quantity,priceach,pricetotal
> A,10-dec-2011,12345,3322,3000,222
> B,1,123,Sprockets Black,30,50,1500
> B,2,333,Sprockets Blue,300,5,1500
> A,11-dec-2011,12346,3311,.....
> etc. 

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