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0
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1answer
15 views

How do I get the some of the values from 2 foreign keys in a table?

I've spent a good amount of time on this but, still have no idea as to the sql query I can use to get the student name, and class name from the payments_per_student table. edit: This using JPA work ...
1
vote
1answer
210 views

Please explain SYSCS_UTIL.SYSCS_CREATE_USER() function

Can someone please explain to me how SYSCS_UTIL.SYSCS_CREATE_USER() works? I tried adding a new user like this: SYSCS_UTIL.SYSCS_CREATE_USER('user', 'someP@ss'), and it gave an exception Error code ...
2
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0answers
110 views

Building a tree in Apache Derby 10.10

I know this question has been asked probably a million times, so please forgive me asking it again. I am not a DBA and have very little knowledge of SQL and Derby, but need some kind of a solution as ...
6
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1answer
1k views

PostgreSQL “freeze”/“unfreeze” command equivalents

In Derby (an embedded database written in Java which is mostly used for testing or prototyping) there are "freeze" and "unfreeze" commands which can be used during an online backup. "Freeze" simply ...
2
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1answer
1k views

Convert Oracle database to Derby

I need to migrate an existing Oracle Database into a Derby one. I want to know if there's a tool, a script or another way to do that work. It is using any of the interesting features of Oracle, as I ...
2
votes
0answers
151 views

Two different ON DELETE paths, how do I need to change the schema?

For a project in school I'm designing a website that sells items via auctions. Think eBay, but on the complexity scale of school project. We went through the process of making an ER Diagram and ...
1
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2answers
2k views

Derby/SQL - How to increase performance when left joining and retrieving varchar columns

Through trial and error I found that if I do a left join such as: SELECT firsttable.id, secondtable.id, secondtable.varcharColumn FROM firsttable LEFT JOIN secondtable ON ...
2
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1answer
2k views

Derby slows down after 1.2 million records

I'm using a Derby database, mass insertions slow down to 1/4 to 1/6 the speed once there are 1.2 million records (about 6 GB database size, one major table, other tables are tiny). Is that normal? Is ...
2
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2answers
121 views

Long JOINS Returns No result all tables have one to many relationship with a particular table [closed]

I have a Table Enterpries with Primary Key 'RCNO'. All other tables have a one to many relationship with Enterprise via it's RCNO column. I make a Join of all the tables and i get nothing. Below is ...
8
votes
3answers
5k views

Does making a field unique make it indexed?

If I make a unique constraint on a field, do I also need to make an index on that field in order to get a scalable insert time? Or is this done for me (even if the index it uses isn't publicly ...
3
votes
1answer
896 views

Are there any good database management applications for JDBC/Java databases?

I am working with an Apache Derby/JavaDB database via JDBC. Before have I been working with MySQL and used phpMyAdmin as a good Database Management tool. Is there any good desktop application for ...
44
votes
3answers
25k views

What are the drawbacks with using UUID or GUID as a primary key?

I would like to build a distributed system. I need to store data in databases and it would be helpful to use an UUID or a GUID as a primary key on some tables. I assume it's a drawbacks with this ...