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How do I avoid loading all child records with the actual table


How do I avoid loading all child records with the actual table

By : user3099763
Date : January 11 2021, 03:34 PM
To fix the issue you can do You can disable lazy loading, in your Jobs model remove virtual from children that you don't want to load.if you want to disable it permanently you must disable it globally more info here
code :


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Join two tables where all child records of first table match all child records of second table

Join two tables where all child records of first table match all child records of second table


By : mattcfish
Date : March 29 2020, 07:55 AM
This might help you Updated!
to Felix for pointing out a flaw in my existing solution (3 years after I originally posted it, hehe). After looking at it again, I think this might be correct. Here I'm getting (1) the customers and limits with matching categories, plus the number of matching categories, (2) the number of categories per customer, (3) the number of categories per limit, (4) I then ensure the number of categories for customer and limits is the same as the number of the matches between the customers and limits:
code :
select
  matches.name,
  matches.limit

from (
    select
      c.name,
      c.customerId,
      l.limit,
      l.limitId,
      count(*) over(partition by cc.customerId, lc.limitId) as matchCount
    from tblCustomer c
    join tblCustomerCategory cc on c.customerId = cc.customerId
    join tblLimitCategory lc on cc.categoryId = lc.categoryId
    join tblLimit l on lc.limitId = l.limitId
) as matches

join (
    select
       cc.customerId,
       count(*) as categoryCount
     from tblCustomerCategory cc
     group by cc.customerId
) as customerCategories
on matches.customerId = customerCategories.customerId

join (
    select
      lc.limitId,
      count(*) as categoryCount
    from tblLimitCategory lc
    group by lc.limitId
) as limitCategories
on matches.limitId = limitCategories.limitId

where matches.matchCount = customerCategories.categoryCount
and matches.matchCount = limitCategories.categoryCount
SQL Query to find Parent records without child records.Both child and parent records are on the same table

SQL Query to find Parent records without child records.Both child and parent records are on the same table


By : Thomas Appleby
Date : March 29 2020, 07:55 AM
hop of those help? A SELF JOIN on the table as follows would give the parents without children.
code :
-- relations (record_id, parent_id)
SELECT parents.record_id 
FROM 
    relations parents
    LEFT JOIN relations children
    ON parents.record_id = children.parent_id
WHERE 
    children.record_id IS NULL
How to delete existing records and insert new records on a mapping/child table in Hibernate/JPA

How to delete existing records and insert new records on a mapping/child table in Hibernate/JPA


By : Mr. Effting
Date : March 29 2020, 07:55 AM
wish helps you I assume that the UserProject mapping is a consciuse choice because of the roles additional data (if not you normally do not map that table).
The orphan removal obviously cannot work as it is referenced by both User and Project table.
code :
public User updateUserDetails(User template){
    User toUpdate = EM.find(User.class,template.getId());
    Set<UserProject> present = template.getUserProjects();//the ones should be kept
    Set<UserProject> toDel = new HashSet<>(toUpdate.getUserProjects());
    toDel.removeAll(present); //the difference so the once should be removed
    Set<UserProjcet> newOnes = new HashSet<>(present);
    newOnes.removeAll(toUpdate.getUserProjects()); //freshly added
    for (UserProject uP : toDel) {
        up.getProject().getUserProjects().remove(uP); //from each project removing reference to UserProject
        toUpdate.getUserProjects().remove(uP);
        EM.remove(uP); //removing the actuall 
    }
    toUpdate.getUserProjects().addAll(newOnes);
    return toUpdate;
}
How to insert the records in child table when records are inserted into parents table in SSIS?

How to insert the records in child table when records are inserted into parents table in SSIS?


By : user5652473
Date : March 29 2020, 07:55 AM
around this issue From your description I take for granted, that you know WHICH child records have to be cretaed for WHICH master record, so I guess there are basiacally two possibilities.
All data is known at runtime: Create a dataflow, which populates the master table Cretae a second dataflow, which populates the child table and connect it to the first dataflow via Succeed constraint
Loading more records than actual in HIve

Loading more records than actual in HIve


By : spears
Date : March 29 2020, 07:55 AM
should help you out If hive.compute.query.using.stats=true; then optimizer is using statistics for query calculation instead of querying table data. This is much faster because metastore is a fast database like MySQL and does not require map-reduce. But statistics can be not fresh (stale) if the table was loaded not using INSERT OVERWRITE or configuration parameter hive.stats.autogather responsible for statistics auto gathering was set to false. Also statistics will be not fresh after loading files or after using third-party tools. It's because files was never analyzed, statistics in metastore is not fresh, if you have put new files, nobody knows about how the data was changed. Also after sqoop loading, etc. So, it's a good practice to gather statistics for table or partition after loading using 'ANALYZE TABLE ... COMPUTE STATISTICS'.
In case it's impossible to gather statistics automatically (works for INSERT OVERWRITE) or by running ANALYZE statement then better to switch off hive.compute.query.using.stats parameter. Hive will query data instead of using statistics.
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