Questions tagged [derby]

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Will Derby, H2, or SQLite give faster load time and/or smaller file size than HSQL?

I have some flat files with the following columns; 3 integers, 3 reals, and 1 varchar(20). For querying I need an index that contains both 1 of the integer columns and the varchar column. Each file ...
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1answer
16 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
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1answer
511 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 ...
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0answers
205 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 ...
7
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1answer
3k 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
2k 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
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0answers
401 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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3answers
3k 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 ...
4
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1answer
3k 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
129 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 ...
10
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3answers
7k 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
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1answer
1k 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 ...
60
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3answers
37k 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 ...