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From "Rui Shen (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (EDGENT-311) support SELECT without any parameters in JdbcStreams
Date Thu, 24 Nov 2016 05:34:58 GMT

    [ https://issues.apache.org/jira/browse/EDGENT-311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15692259#comment-15692259

Rui Shen commented on EDGENT-311:

Okay, thanks for your comprehensive explanation - I am clear now. Regarding the question if
"one-time statement execution" case is common one, I am not quite sure for now. If it is,
I will contact you later. Thanks. 

> support SELECT without any parameters in JdbcStreams
> ----------------------------------------------------
>                 Key: EDGENT-311
>                 URL: https://issues.apache.org/jira/browse/EDGENT-311
>             Project: Edgent
>          Issue Type: Improvement
>          Components: Connectors
>    Affects Versions: Apache Edgent 1.0.0
>            Reporter: Rui Shen
>            Priority: Minor
> Now I am trying to run a SELECT statement without parameters (e.g "select id,name,age
from person") using JdbcStreams. But I found there is no straightforward way to do this. Looks
like the APIs of JdbcStreams is designed for only prepared statement with parameters .
> However, I found a workaround to make this - always create a TStream with one tuple but
in the ParameterSetter, does nothing. Although this works, it looks uncomfortable. Are you
going to support this in the future release?
> Topology t = this.newTopology("testSelect_WithParameters");
> JdbcStreams db=new JdbcStreams(ds,(ds)=>
> {ds.getConnection()}
> );
> TStream<String> stream=t.collection(Arrays.asList(new String[]
> {"dummy"}
> )); // to execute the sql, always needs to create a TStream containing one tuple.
> ParameterSetter<String> paramSetter=(s,stmt)->{}; //do nothing here
> ResultsHandler<Object[], JsonObject> rh = (tuple, rs, exc, consumer) -> {};
> db.executeStatement(stream, "select id,name,age from person", paramSetter,rh);

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