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13.17. JPA Translator
The JPA translator, known by the type name jpa2, can reverse a JPA object model into a relational model, which can then be integrated with other relational or non-relational sources.
The JPA Translator currently has no import or execution properties.
JPA source procedures may be created using the teiid_rel:native-query extension. The procedure invokes the native-query similar to an native procedure call with the benefits that the query is predetermined and that result column types are known, rather than requiring the use of ARRAYTABLE or similar functionality.
Warning
This feature is turned off by default because of the security risk this exposes to execute any command against the source. To enable this feature, set the execution property called SupportsDirectQueryProcedure to true.
Note
By default the name of the procedure that executes the queries directly is native. Override the execution property DirectQueryProcedureName to change it to another name.
The JPA translator provides a procedure to execute any ad-hoc JPA-QL query directly against the source without Teiid parsing or resolving. Since the metadata of this procedure's results are not known to Teiid, they are returned as object array. User can use ARRAYTABLE can be used construct tabular output for consumption by client applications. Teiid exposes this procedure with a query structure.
In this select query, the "search" keyword is followed by a query statement:
SELECT x.* FROM (call jpa_source.native('search;FROM Account')) w,
ARRAYTABLE(w.tuple COLUMNS "id" string , "type" string, "name" String) AS x
SELECT x.* FROM (call jpa_source.native('search;FROM Account')) w,
ARRAYTABLE(w.tuple COLUMNS "id" string , "type" string, "name" String) AS x
In this delete query, the the "delete" keyword is followed by JPA-QL for a delete operation.
SELECT x.* FROM (call jpa_source.native('delete;<jpa-ql>')) w,
ARRAYTABLE(w.tuple COLUMNS "updatecount" integer) AS x
SELECT x.* FROM (call jpa_source.native('delete;<jpa-ql>')) w,
ARRAYTABLE(w.tuple COLUMNS "updatecount" integer) AS x
In this sample, the "update" keyword must be followed by JPA-QL for the update statement.
SELECT x.* FROM
(call jpa_source.native('update;<jpa-ql>')) w,
ARRAYTABLE(w.tuple COLUMNS "update_count" integer) AS x
SELECT x.* FROM
(call jpa_source.native('update;<jpa-ql>')) w,
ARRAYTABLE(w.tuple COLUMNS "update_count" integer) AS x
In this create query, the create operation sends "create" word as a marker and send the entity as the first parameter:
SELECT x.* FROM
(call jpa_source.native('create;', <entity>)) w,
ARRAYTABLE(w.tuple COLUMNS "update_count" integer) AS x
SELECT x.* FROM
(call jpa_source.native('create;', <entity>)) w,
ARRAYTABLE(w.tuple COLUMNS "update_count" integer) AS x
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