[teiid-issues] [JBoss JIRA] Commented: (TEIID-1326) API request: rewrite query/command before it reaches the teiid planner
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https://issues.jboss.org/browse/TEIID-1326?page=com.atlassian.jira.plugin...
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Steven Hawkins commented on TEIID-1326:
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I should add that this approach has several advantages over the current direct
manipulation of Table metadata records (possibly through ddl).
1. that the view definitions can be made user specific, without api changes to the
metadata classes.
2. a single class can be consulted which can simplify updating the same view across
multiple vdb versions.
3. dml or a single instance administrative call would need to made on each member in a
cluster (we may address this through a live operational repository in the future)
4. related to number 3, changes to the metadata records are not-persistent.
So having this metadata update or costing updates, etc. through a real operational
repository with notifications can be a long term direction, but for now we'll have to
settle.
API request: rewrite query/command before it reaches the teiid
planner
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Key: TEIID-1326
URL: https://issues.jboss.org/browse/TEIID-1326
Project: Teiid
Issue Type: Feature Request
Components: Query Engine
Affects Versions: 7.1
Reporter: Mark Addleman
Assignee: Steven Hawkins
Fix For: 7.4
I'd like an API to inspect and rewrite a user query/command before it reaches the
Teiid planner. The use case is to rewrite the query/command to implement view-like
capabilities. For example:
SELECT a,b,c FROM table1 AS t WHERE t.a='xyz' would be rewritten as:
SELECT a,b,c FROM (SELECT a,b,c FROM table2 UNION SELECT a,b,c FROM table3) AS t
I imagine this API would be similar to the translator API: it would receive a data
structure representing the query/command and use a visitor to rewrite the query. As a
convenience, it would be nice to have something similar to the SQLConversionVisitor.
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