Problem with Database connection table reader

[giad]

Hi everyone
have a problem with the database connection table reader: i have connected a postgreqsl DB and after some joins I need the database connection table reader but i do not find it. I have only the database connection table reader (legacy). Why?

I cannot connect the legacy to postgresql unfortunately…
where can I find the one not legacy?

Many thanks
Giada

[mlauber71]

@giad welcome to the KNIME community.

With the new DB nodes you would have to use the

DB Reader

Or the

DB Query Reader

The whole thing with the new nodes looks like this

KNIME and SQLite - simple example (4.0 New DB nodes) – mlauber71

Compared to this

KNIME and SQLite - simple example (3.7 Legacy DB nodes) – mlauber71

[giad]

Thanks!! It works with db reader, but I cannot write anything in “flow variables”. How can I set variables in the db reader? I have connected the db reader to a db joiner…

Thanks again
Giad

[mlauber71]

Not excatly sure I follow. If you want to familiarize yourself with Flow variables a good starting point might be @armingrudd blog entry about them. Also you could take a look at the examples where they are constantly used.

https://blog.statinfer.com/knime-spirits-at-your-service/

Also there is the official course
https://www.knime.com/knime-introductory-course/chapter7/section1

[giad]

@armingrudd Hi Armin,
I have seen your blog but I have a question for you:

I connected a postgresql, then I did a db table connector and db joiner…then, I need to connect a db reader but I should set flow parameters. How can I do it? I have tried to set flow parameters with string input but I cannot connect it to db reader…Can you help me please?

[armingrudd]

Hi @giad and welcome to the KNIME forum,

What do you want to do with flow variables? DB Reader has no configurations, it just reads the table you have already queried.

[giad]

I thought to set flow variables for db reader because I see this window into the db reader configuration:

so, do not I need to set flow variables?
In this case, how can I conet db reader to a db joiner for example? because it does not work without flow variables…

Many thanks

[ipazin]

Hi there @giad,

didn’t understand why do you want to use flow variables? (Flow variables are for parameterization.) Why do you want to connect DB Reader node to DB joiner node? Can you explain it a bit more?

Br,
Ivan