object-oriented-database

问题 What is the best way to store instances of a class to file/database? We have a base class called Command and loads of derived classes. Users create instances of these classes by adding commands to a graphical designer where they can configure them. (Set the properties). We then need a way to store these "commands" to a file without losing any information. One idea was to use db4o, but the GPL license is not acceptable for this project. Any suggestions or code samples? Update: (In order to "de

问题 I'm very impressed with my initial tests with db4o. However, i'm wondering just how many enterprise class websites are out there powered by db4o, i couldn't see any on the main website? I can't see any reason why db4o should not be used. There appears to be decent enough support for transactions and ways to handle concurrency for example. Anyone got a list of websites i could look at? 回答1: See: http://developer.db4o.com/Projects/html/projectspaces/gaabormarkt.html 回答2: A particular search

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 4 days ago . I'm looking for a library that lets me run SQL-like queries on python "object databases". With object database I mean a fairly complex structure of python objects and lists in memory. Basically this would be a "reverse ORM" - instead of providing an object oriented interface to a relational database, it would

问题 I've been using relational databases + object relational mappers for object persistence. I don't think this is a truly adequate solution for persistence, because it adds unnecessary overhead. It also forces me to fit objects in a table-like structure, which sometimes can't be done gracefully - it's like fitting a square in a circle - it won't work well. Now, I am aware that there are object-oriented databases out there, but for one thing they lack support, and also the relational model works

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 6 years ago . Please recommend some material about implementing Object-Oriented Databases for dynamic languages (interested in Ruby). I realise that

问题 I am working on a small educational project to exercise perst.net. We have a tiny design problem, that is how to best resolve the relation between two classes of objects, that is the participant and championship . It is a many to many relation as participant can take part in many championships and championships can have a multiple participants . Please advise how to do this best in C#, should I use the 'relational DB like' technical class? 回答1: If you're looking for an object oriented (or

问题 Whats the cons and pros of using a object database or relational database for regular web development which involves a lot of CRUD? UPDATE: I reopened the bounty reward in order to give Neville it. 回答1: Relational database: Pros: Established technology - lots of tools, developers, resources Wide range of Open Source and commercial products Known to scale to very large sites, and very high throughput Expresses many problem domains in a logical and "programmable" way Fairly standard language

问题 Currently I have a class called DBAdapter that has an inner class called DatabaseHelper which extends SQLiteOpenHelper. Without the actual implementation it would look like this (in a high level): public class DBAdapter { public Cursor selectAllBooks(); public List<Book> getAllBooks(); //This would handle the cursor for you private class DatabaseHelper extends SQLiteOpenHelper{} } This way, the calling activity could simply call dbAdapter.getAllBooks(), as opposed to having to cycle through

问题 I have a Python 3.5 program that creates an inventory of objects. I created a class of Trampoline s (color, size, spring, etc.). I constantly will create new instances of the class and I then save a dictionary of them. The dictionary looks like this: my_dict = {name: instance} and the types are like so {"string": "object"} My issue is that I want to know how to save this inventory list so that I can start where I left off the last time I closed the program. I don't want to use pickle because

问题 I'm new to PostgreSQL and I'm struggling to understand how to use a reference to an 'instance' (or row) from a table as a value within a row of another table. Here is my desired result: class User{ int age; Post[] posts; } class Post{ int postId; ... } // Sql script sqlMain{ User k = new User(20); k.addPost(10, ...); } As you can see, I want an (dynamic prefereably, like an ArrayList) array of posts as an attribute of a user. So far I have the following Script: CREATE TABLE Post( postId INT )