[
https://issues.apache.org/jira/browse/EDGENT-311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15675658#comment-15675658
]
Rui Shen commented on EDGENT-311:
---------------------------------
The key thing here is not ParameterSetter, but the first parameter TStream in
db.executeStatement method. My understanding is that this stream provides the
needed SQL parameters, but if there is no parameters (i.e. no "?") in my SELECT
statement, the stream parameter is supposed to be set to return nothing. But
the current result is that if the stream parameter returns nothing, you won't
see the SQL is executed. You could give a try. So that's why I put a "dummy" in
the stream parameter,which's purpose is just to trigger the SQL execution, but
doesn't it look weird? :).
> 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);
>
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
