I have an existing Schema definition in MySql database. I created the schema using MySql Workbench.
I wish to access the schema from my Lift-Scala-Squeryl code. I know that a simple way would be to manually define the schema structure using Squeryl data objects.
Is there an automated way to generate Squeryl data objects out of existing MySql schema?
I've found the following general question, but I'm sure there can be a way to generate a naive structure, although not accurate, it will allow a better starting point for the manual work.
Thanks, David.
Max, Squeryl's creator, had suggested that this would be a good idea a while back. Here is the google group discussion.
You may not be too pleased with me for this, but I think I talked him out of it :) So, to my knowledge, there isn't a way to do it. Besides the issues I pointed out in that thread, the fact that Squeryl can work in multiple modes (primitive types, custom types, lift record types) it would be a difficult thing to do and get right for everyone.
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I am using MongoDB first time here. Is there any best way to transfer bulkdata from mysql into MongoDB. I try to search to in different ways but i did not find.
You would have to physically map all your mysql tables to documents in mongodb but you can use an already developed tool.
You can try: Mongify (http://mongify.com/)
It's a super simple way to transform your data from a MySql to MongoDB. It has a ton of support for changing your existing schema into a schema that would work better with MongoDB.
Mongify will read your mysql database, build a translation file for you and all you have to do is map how you want your data transformed.
It supports:
Updating internal IDs (to BSON ObjectID)
Updating referencing IDs
Typecasting values
Embedding Tables into other documents
Before filters (to change data manually before import)
and much much more...
There is also a short 5 min video on the homepage that shows you how easy it is.
Try it out and tell me what you think.
Please up vote if you find this answer helpful.
I have a very large Json object that i want to put in a nosql database.
I would like to know:
first, how to generate the database schema based on that Json object?
second, is there a way to put this object automatically in the database, without manually specifying which value (in json object) goes in which column (in the database)?
I hope I was clear enough. Thanks!
Since you haven't specified which NoSQL database you're using in particular, for convenience, I'll assume you're using MongoDB when I talk about things that are implementation specific.
First off, you should know that NoSQL databases by nature are "schema-less". You still could implement your own schema (in your app, not the db), but that's optional, and mostly done just for validation purposes or to let future developers understand the planned structure of your data better. Read the Dynamic Schemas section in this article to know more. Here is a SO answer explaining how you would do that in mongoose and here is the official guide/doc for it.
Second, NoSQL databases don't work in terms of columns or rows. Rather, you need to think in terms of collections and documents. So to answer your question : Yes, when you have a JSON object, you shove it in directly (before applying any required formatting if you've implemented a schema like in above). You don't enter data value by value (unless you've intentionally set it up to do so).
It sounds to me that you need to strengthen your fundamental understanding of how NoSQL works as you seem to be confusing yourself with concepts that belong to other DBMS. Here is a neat slideshow to get you started and the previous article I linked you to also gives you a decent introduction.
After you're done, consider installing MongoDB or something similar and just playing around with the command line interface to get a good hang of it.
I don't know completely what I want, but surely someone has had the same need, and has solved it in a far better manner than I could:
I'm looking for some mechanism to extract the data definition of a mySQL table from the database and allow it to be queried for the list of columns and their definitions, as part of a routine to dynamically construct DML? It would also be good to have the table parameters (e.g. ENGINE, INDEX, etc.) available, too.
Our databases aren't particularly advanced, and I certainly don't have an encyclopedic knowledge of SQL DDL, so what I came up with probably wouldn't be of much use to anyone else. Is there something already out there in Perl - preferably object-oriented - to do this, at least for mySQL?
Yes, there's a Perl package SQL::Translator, part of a toolset called SQLFairy. It parses SQL DDL from an SQL script or from a live database instance. It supports several RDBMS, including MySQL.
Then it offers tools to do schema conversions, schema diffs, and a bunch of other cool stuff.
http://metacpan.org/pod/SQL::Translator
http://sqlfairy.sourceforge.net/
I found the docs are better than most Perl projects, but still I had to read the code to understand how to use it in the way I wanted to.
The DBI interface has a set of "Catalog Methods": http://metacpan.org/pod/DBI#Catalog-Methods.
There is a similar StackOverflow question you can look at: How do I get schemas from Perl's DBI?
I need help from you experts about practices regarding database development. I have a few questions regarding MySQL databases:
Is there a way for MySQL that a database and its structure is developed in an XML language and then converted to a fully functional MySQL database?
Is it possible to generate the XML source file from question 1 (see above) based on an existing database in MySQL ?
As far as I know, XML is not suitable for developing database structures. However can we say that XML is a language to demonstrate hierarchical structures and a MySQL database also shows a hierarchical structure, so in fact it is suitable for database development?
Thank you very much!
You can certainly store XML data in MySQL. You can also use any number of approaches to converted hierachical XML data into individual relational database field representations.
I would however say that if you just want to work with intact XML documents, you might look to go the NoSQL route, which is really better suited for this type of data storage. You also might consider JSON as the format for storage as it is more concise (saves space and transmissions badnwidth) and is more aligned with the popular NoSQL data stores out there.
1) yeah there is a way, but you should check out mongodb if you want a dynamic database structure, it was developed with that in mind. also, unless you need the rss features of xml or something similar, you might want to consider using json as a format for you documents.
2) json and mongodb work very well together to quickly and easily get documents in and out of the db. you can technically do it in mysql as well, but you might spend more time scripting in php or ruby to get the desired format you want.
3) you could use xml to demonstrate your db structure because of it's loose structure, but i'm not sure it would be intuitively clear to others. hard to say, really depends on how you implement it and how complicated your db structure is going to be.
I was reading Fastest Way to Find Distance Between Two Lat/Long Points and thought that the solution to this question was a good way to solve a problem of mine. However, I also using django with mysql so when I save a model object, it's saved with the django model types. Of course the solution to that question requires me to use certain functions/object in mysql that django itself doesn't have as a model type. I realize that geodjango has the types, but I don't think I need/want all that extra functionality when I only really need this one solution(i.e. I don't want to install geodjango). So how do I store those mysql geometry datatypes using django model types? Do I have to write some myself or directly inject sql commands? Can someone point me to some sample code? Or perhaps there's a really, really lightweight geodjango that's super easy to install/setup?
Geodjango is part of contrib. if you have django installed, and you have the bindings for spatial data types in mysql, you have geodjango setup, it's really not any harder than that, and now your queries are not only really easy, you get lots more queries available too.