CODEWITHSUNDEEP
smalltalkpharo
Carl Wilson
Carl Wilson

Reputation: 54

Pharo 2.0 Smalltalk and PostgresV2

Trying to return results from a table in a DB. This code works:

| connection results |

PGConnection defaultConnectionArgs
hostname: '*****.awebservice.com';
portno: 1234;
databaseName: '*****';
userName: '********';
password: '**************'.

connection := PGConnection new.

connection startup.
results := connection execute: 'SELECT uid, code, name FROM public.Project'.
Transcript show: results rows.

But in analysing it I want to know how to access a single row. Where in Smalltalk classes is ROWS? If I do further processing of the OrderedCollection returned (results) with this code:

results rows do: [:row | | data |
data := row dataKeyedByFieldName.
Transcript show: 'Uid: ''', (data at: 'uid') , ''''; cr.
Transcript show: 'Code: ''', (data at: 'code') , ''''; cr.
Transcript show: 'Name: ''', (data at: 'name') , ''''; cr; cr]. 
connection terminate.

I get an error: Instances of SmallInteger are not indexable. I will come clean and say I got this off the web but nowhere can I find either ROWS or DATAKEYEDBYFIELDNAME as methods in any Smalltalk class.

Edit: OK I found out that the return variable from connection: execute is of type PGAsciiRow and the method #dataKeyedByFieldName is to enable iteration by using name index instead of simple numeric. But still don't know where the error is coming from. The following is a stack trace:

    errorNotIndexable
    "Create an error notification that the receiver is not indexable."
    self error: ('Instances of {1} are not indexable'
    translated format: {self class name})

Upvotes: 1

Views: 635

Answers (1)

EstebanLM
EstebanLM

Reputation: 4357

most probably 

data at: 'uid'

(or 'code') is answering an integer number. Then, this line: 

Transcript show: 'Uid: ''', (data at: 'uid') , ''''; cr.

should better be written: 

Transcript show: 'Uid: ''', (data at: 'uid') asString, ''''; cr.

something like that :)

Upvotes: 1

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