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https://issues.apache.org/jira/browse/SAMZA-483?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14275815#comment-14275815
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Milinda Lakmal Pathirage commented on SAMZA-483:
------------------------------------------------
>From Streaming SQL object model, I am thinking about something similar to
>following (we can go for a more generic version, below is just an idea what it
>will be like):
public class SelectQuery {
private FromClause fromClause;
private WhereCaluse whereCaluse;
public void setFromClause(FromClause fromClause) {
this.fromClause = fromClause;
}
public void setWhereCaluse(WhereCaluse whereCaluse) {
this.whereCaluse = whereCaluse;
}
}
In case of relational algebra it will be something like this:
/ Recursive data structure
public class RelExpr {
// This can be a subquery, window operation, etc.
private RelExpr operand1;
private RelExpr operand2;
private BinaryOp binaryOp;
private SelectionClause selection;
private ProjectionClause projection;
private WindowClause window;
// In case the relational algebra expression reduced to a reference (stream
or relation)
private String identifier;
// TODO: We have to add join conditions, partition by clauses as well.
}
Above models are not final and are just for demonstration purposes only.
> A common representation of relational algebra for streaming SQL
> ----------------------------------------------------------------
>
> Key: SAMZA-483
> URL: https://issues.apache.org/jira/browse/SAMZA-483
> Project: Samza
> Issue Type: Sub-task
> Reporter: Yi Pan (Data Infrastructure)
> Priority: Minor
> Labels: project
>
> Per discussion with [~criccomini] and [~milinda], we agreed that it seems to
> be a good idea to define a common representation of relational algebra on top
> of the operators defined in the operator layer (see SAMZA-482), which can be
> the common base that we can use to generate the description/configuration of
> a Samza job.
> This common layer can also be used by DSL-like language parser as a result of
> parsing a DSL program.
> Some additional requirements needed in addition to pure relational algebra:
> 1) the common representation should include window operators and stream
> operators (i.e. IStream/DStream/RStream)
> 2) the common representation should include description on parallelism of the
> jobs (i.e. how many partitions the resultant Samza job will use)
> Some references:
> http://web.cs.wpi.edu/~mukherab/i/DCAPE.pdf
> https://cs.uwaterloo.ca/~david/cs848/stream-cql.pdf
> http://davis.wpi.edu/dsrg/PROJECTS/CAPE/publications.htm
> http://davis.wpi.edu/dsrg/PROJECTS/CAPE/slides.htm
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