When I use eclipselink (or toplink) , I can set the "eclipselink.jdbc.bind-parameters" hint to query, but it not works in OpenJpa( or Kodo), what should I do?
I don't believe that OpenJPA has an equivalent parameter. If I understand the eclipselink documentation correctly, OpenJPA always parameterizes.
Related
I want to parser the sql query using calcite to do some SQL equivalence verification. But I found the default setting of calcite don't support dialect-specific operator such as TO_TIMESTAMP. The error is below:
No match found for function signature TO_TIMESTAMP(<CHARACTER>, <CHARACTER>)
The answer here said I can use jdbc to change the setting of calcite. But I cannot found where to use jdbc string to change the setting. Should I use some API in calcite to put the jdbc statement into calcite?
If you're not invoking Calcite via JDBC, how are you calling it? Other APIs to Calcite have an equivalent of the JDBC fun parameter in the answer you reference, but it's difficult to answer your question without more specifics.
According to the update on hsqldb.org listed here: http://hsqldb.org/web/features200.html
It now supports the mysql syntax ON DUPLICATE KEY in hsqldb 2.3.4, yet Im still getting sql errors when trying to run it. If im reading correctly I may need to set certain flags. But I cant find what to set to be able to use this synatx.
MySQL compatibility is documented in the Guide http://hsqldb.org/doc/2.0/guide/compatibility-chapt.html#coc_compatibility_mysql
You need to execute SET DATABASE SQL SYNTAX MYS TRUE or the equivalent URL property sql.syntax_mys=true to enable it.
I had understood that jOOQ would simulate SQL MERGE on systems (such as PostgreSQL) that don't support it.
I have a table with a serial (autoincrement) "id" column and a string "uri" column. I want to use numeric IDs instead of URIs in my database, so I have to make sure I have a URI in the ID lookup table. So following the example in the jOOQ manual, I thought this would work:
createDSLContext().mergeInto(tableByName("uris"))
.using(createDSLContext().selectOne())
.on(fieldByName("uri").equal("http://example.com/"))
.whenNotMatchedThenInsert(fieldByName("uri"))
.values("http://example.com/").execute();
This gives me a DataAccessException saying something like:
SQL [merge into "uris" using (select 1) on "uri" = ? when not matched then insert ("uri") values (?)]; ERROR: syntax error at or near "merge"
But then the log says jOOQ goes ahead and tries to execute the query with bind values. But the table is never updated. So I'm guessing the jOOQ doesn't simulate MERGE on PostgreSQL?
So I then try the H2 database syntax:
createDSLContext().mergeInto(tableByName("uris"), fieldByName("uri")).values(uri.toString()).execute();
I get:
The H2-specific MERGE syntax is not supported in dialect : POSTGRES
What!? But the jOOQ documentation says that the H2 syntax "can be fully simulated by jOOQ for all other databases that support the SQL standard." Surely PostgreSQL supports the SQL standard. Does it really mean "...the SQL standard version of MERGE?"
Is there any way to get PostgreSQL support for MERGE via jOOQ, or am I stuck doing the same workarounds I would do anyway?
To be sure if a given SQL feature is supported by jOOQ for your database, please consider the Javadoc's #Support annotation on the relevant DSL method. This is also documented in the manual. In this case, DSLContext.mergeInto(), where you can see that this statement is currently only supported for these SQLDialects:
#Support(value={CUBRID,DB2,HSQLDB,ORACLE,SQLSERVER,SYBASE})
MERGE is a very powerful statement that is not really easy to emulate if your database doesn't natively support it.
"can be fully simulated by jOOQ for all other databases that support the SQL standard." Surely PostgreSQL supports the SQL standard. Does it really mean "...the SQL standard version of MERGE?"
Yes of course, the SQL standard MERGE statement must be supported :-) We'll clarify this in the manual. I have registered issue #3183 for this.
Is there any way to get PostgreSQL support for MERGE via jOOQ, or am I stuck doing the same workarounds I would do anyway?
Right now, unfortunately, we don't have a solution for this in PostgreSQL. Feel free to discuss possible solutions on the jOOQ User Group.
Yes , it can support which database support the merge in SQL stand.
but postgresql unsupport this feature in SQL standard.
Please see
F312 MERGE statement
F313 Enhanced MERGE statement
F314 MERGE statement with DELETE branch
http://www.postgresql.org/docs/9.3/static/unsupported-features-sql-standard.html
I'm looking for a way to programmatically execute arbitrary SQL commands against my DB.
(Hibernate, JPA, HSQL)
Query.createNativeQuery() doesn't work for things like CREATE TABLE.
Doing LOTS of searching, I thought I could use the Hibernate Session.doWork().
By using the deprecated Configuration.buildSesionFactory() seems to show that doWork won't work.
I get "use lacks privilege or object not found" for all the CREATE TABLE statements.
So, what other technique is there for executing arbitratry SQL statements?
There were some notes on using the underlying JDBC Statement, but I haven't figure out how to get a JDBC Connection object from Hibernate to try that.
Note that the hibernate.hbm2ddl.auto=create setting will NOT work for me, as I have ARRAY[] columns which it chokes on.
I don't think there is any problem executing a create table statement with a Hibernate native query. Just make sure to use Query.executeUpdate(), and not Query.list() or Query.uniqueResult().
If it doesn't work, please tell us what happens when you execute it, and join the full stack trace of the exception and the SQL query you're executing.
"use lacks privilege or object not found" in HSQL may mean anything, for example existence of a table with the same name. Error messages in HSQL are completely misleading. Try listing your tables using DatabaseMetadata - you have probably already created the table.
I am using Nhibernate 2.12 and am having an issue with LockMode. I am trying to add NoLock to the sql statement on an alias. When I do this using a crieria that doesn't provide a projectionlist it works fine. But when I add a projection list it gives me a nasty 'Object reference not set to an instance of an object' error on the NHibernate.Loader.Criteria.CriteriaLoader.ApplyLocks(SqlString sqlSelectString, IDictionary`2 lockModes, Dialect dialect) part of nhibernate.
Am I missing something?
Phil
I think projections is not support locking, so try to not use locking when using projections.