I was created my project in spring 4 MVC + Hibernate with MongoDB. now, I have to convert it into the Hibernate with MySQL. my problem is I have too many collections in MongoDB the format of bson and json. how can I convert that file into MySQL table format? is that possible?
Mongodb is a non-relational database, while MySQL is relational. The key difference is that the non relational database contains documents (JSON objects) which can contain hierarchical structure, where as the relational database expects the objects to be normalised, and broken down into tables. It is therefore not possible to simply convert the bson data from MongoDB into something which MySQL will understand. You will need to write some code that will read the data from MongoDB and the write it into MySQL.
The documents in your MongoDB collections represent serialised forms of some classes (POJOs, domain object etc) in your project. Presumably, you read this data from MongoDB deserialise it into its class form and use it in your project e.g. display it to end users, use it in calculations, generate reports from it etc.
Now, you'd prefer to host that data in MySQL so you'd like to know how to migrate the data from MongoDB to MySQL but since the persistent formats are radically different you are wondering how to do that.
Here are two options:
Use your application code to read the data from MongoDB, deserialise it into your classes and then write that data into MySQL using JDBC or an ORM mapping layer etc.
Use mongoexport to export the data from MongoDB (in JSON format) and then write some kind of adapter which is capable of mapping this data into the desired format for your MySQL data model.
The non functionals (especially for the read and write aspects) will differ between these approaches but fundamentally both approaches are quite similar; they both (1) read from MongoDB; (2) map the document data to the relational model; (3) write the mapped data into MySQL. The trickiest aspect of this flow is no. 2 and since only you understand your data and your relational model there is no tool which can magically do this for you. How would a thirdparty tool be sufficiently aware of your document model and your relational model to be able to perform this transformation for you?
You could investigate a MongoDB JDBC driver or use something like Apache Drill to facilitate JDBC queries onto your Mongo DB. Since these could return java.sql.ResultSet you would be dealing with a result format which is more suited for writing to MySQL but it's likely that this still wouldn't match your target relational model and hence you'd still need some form of transformation code.
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This may be a naive question or a requirement. I parse huge raw data and restructure it into a set of JSON files. These JSON files reside in a directory). I would like to avoid setting up any NoSql database such as - MongoDB (any database for that matter)
Based on these JSON files, I would like to setup express models so that I can make queries to JSON files. There won't be any Create, Update, and Delete operations user will perform.
I was looking for a module similar to mongoose which can make things simpler.
ABAP Databases, oracle, MaxDB et al., are mostly RDBMS. Right now, I have a JSON structure that cannot be normalised and hence I want to store it as is. So, I want a MongoDB like Object store in ABAP.
What's the best way to achieve this? Is data cluster an option? Perhaps the only option?
I don't think you can connect to some other then supported DBs directly from ABAP. If you have Netweaver Java, you can call some custom Java application, which accesses MongoDB. You can check SAP Hana if there is something similar.
In ABAP you interact with RDBMS via ABAP Dictionary.
It supports data types like LCHR, STRING, RAWSTRING. Checkout docs for more details.
Data cluster is one option, but you can simply use a binary type DB field for storing the JSON data.
There is a method called transformation in ABAP, which converts from ABAP data to XML/JSON data and vice-versa.
There's a simple example on the following blog:
https://blogs.sap.com/2013/07/04/abap-news-for-release-740-abap-and-json/
Comments on the blog page contain more info.
So the situation that I have is,I am developing a form builder like application which needs to be custom for all users. The form is hosted and response collected in database. Now what is the correct way to do the same in mysql like database.
For an example assume two forms, one with a text field and another with radio button and text field. Also once that model is created is there any way to use django forms, or will I have to go some other way.
Recently mysql introduced JSON fields.
As of MySQL 5.7.8, MySQL supports a native JSON data type that enables
efficient access to data in JSON (JavaScript Object Notation)
documents. The JSON data type provides these advantages over storing
JSON-format strings in a string column:
Even if you don't have the latest version of mysql it's still possible to save JSON data in a varchar field and is quite a popular solution supported by many third party libraries that provide JSON support for Django.
The reason that a third party library is needed is because Django doesn't have a built in JSONField. One has been added recently for Postgresql but mysql is still lagging behind.
Alternative that does not involve mysql is to use redis. Django has excellent support for redis and as you know redis hashes are very similar to python dictionaries. ORM support requires third party libraries as with mysql json fields. However it's simpler to think of redis as a python dictionary that can be persisted across sessions and queried very fast. Last but not least the hash is just the tip of the iceberge.
I have exported data from firebase in one json file,I want to create a mysql tables using this json file.Is there any way to do so?
Try to use MySql Workbench. It looks provide Json format to import.
https://dev.mysql.com/doc/workbench/en/wb-admin-export-import.html
I guess you could convert your json into csv and import that into mysql like it has been described here: Importing JSON into Mysql
However, I am not really sure how that would be connected to django (since you mentioned it in your questions title). It might be helpful if you would describe in more detail what you want to do.
You can store data with very dynamic schema with Firebase. MySQL is a traditional RDBMS, you have to analyze the structure of your dataset and decide what parts do you want to convert to relational format.
There's a good news however: there are several packages which support JSON fields on models: https://www.djangopackages.com/grids/g/json-fields/
There's one MySQL specific also: https://django-mysql.readthedocs.org/en/latest/model_fields/json_field.html
Such JSON data is queryable and updatable. So if your dataset has some varying schema parts, you can store those in JSON format.
Starting from MySQL 5.7 JSON data is even natively supported by the DB. Read more here:
https://django-mysql.readthedocs.org/en/latest/model_fields/json_field.html
I have an existing MySQL database, I would like to import the schema into Xcode and create a Core Data data model.
Is there a way (tool, process) to import the CREATE statements so I don't have to build the models "by hand"?
As an intermediary step I could convert to SQLite, I'm not worried about the relationships, foreign keys etc just auto-generating the Entities (Tables) and Properties (Columns).
Actually I needed the feature so badly too that I have decided to make an OSX utility to do so. BUT... then I found a utility in the Mac Appstore that (partially) solves this problem (it was free for some time, I do not know its current state). Its called JSONModeler and what it does is parsing a json tree and generates the coredata model and all derived NSManagedObject subclasses automatically. So a typical workflow would be:
Export the tables from MySQL to xml
Convert the xml to json
Feed the utility with that json and get your coredata model
Now, for a more complicated scenario (relationships etc) I guess you would have to tweak your xml so it would reflect a valid object tree. Then JSONModeler will be able to recreate that tree and export it for coredata.
The problem here is that entities are not tables and properties are not columns. Core Data is an object graph management system and not a database system. The difference is subtle but important. Core Data really doesn't have anything to do with SQL it just sometimes uses SQL as one its persistence options.
Core Data does use a proprietary sqlite schema and in principle you can duplicate that but I don't know of anyone who has succeeded in a robust manner except for very simple SQL databases. Even when they do, its a lot of work. Further, doing so is unsupported and the schema might break somewhere down the line.
The easiest and most robust solution is to write a utility app to read in the existing DB and create the object graph as it goes. You only have to run it once and you've got to create the data model anyway so it doesn't take much time.