I'm using a static database that I created with SQLite Database Browser. I put it in my assets folder and built a code to copy the database to a database variable (Does that make sense?) so I could read information from it. Problem is I don't know how - mostly the SQL queries involved - and what are your suggested methods do to that? In other words, what methods should I add to my Database Handler class (Or data adapter?) in order to present the data in a list view, for example.
Thank you for all your help.
Read the Android database documentation.
Copying your database from the assets folder is typically done in the onCreate and/or onUpgrade functions of your SQLiteOpenHelper-derived class.
This tutorial covers the basics:
Using the SQLite Database with ListView
As for naming things: use whatever names make sense in your application.
Related
For a database-per-service architecture, how do you guys manage your static data for each microservice? I want to make it easy for a new developer to jump in and get everything up and running easily on their local machine. I'm thinking of checking the entire database with static data into source control with Docker bind mounts so people can just docker-compose up the database service locally (along with whatever other infrastructure services they might need to run and test their microservice).
I know each microservice might need to handle this in their own way, but I'd like to provide a good default template for people to start with.
Making a standard for how to do this sort of goes against the reason for making microservices, i.e. that you can adapt each microservice to the context it exists in.
That being said, Postgres, Mongo and MySQL all run scripts in /docker-entrypoint-initdb.d when initializing a fresh database instance. The scripts have to fit the database obviously, but it's a fairly standardized way of doing it.
They all have descriptions of how to do it on the image page on docker hub.
You can either get your scripts into the container by making a custom image that contains the scripts or you can map them into the directory using a docker-compose volume mapping.
There are some databases that don't have an easy way to initialize a new database. MSSQL comes to mind. In that case, you might have to handle it programmatically.
I have a Django project with multiple apps. They all share a db with engine = django.db.backends.postgresql_psycopg2. Now I want some functionality of GeoDjango and decided I want to integrate it into my existing project. I read through the tutorial, and it looks like I have to create a separate spartial database for GeoDjango. I wonder if there is anyway around. I tried to add this into one of my apps' models.py without changing my db settings :
from django.contrib.gis.db.models import PointField
class Location(models.Model):
location = PointField()
But when I run syncdb, I got this error.
File "/home/virtual/virtual-env/lib/python2.7/site-packages/django/contrib/gis/db/models/fields.py", line 200, in db_type
return connection.ops.geo_db_type(self)
Actually, as i recall, django.contrib.gis.db.backends.postgis is extension of postgresql_psycopg2 so you could change db driver in settings, create new db with spatial template and then migrate data to new db (South is great for this). By itself geodjango is highly dependent on DB inner methods thus, unfortunately, you couldn't use it with regular db.
Other way - you could make use of django's multi-db ability, and create extra db for geodjango models.
Your error looks like it comes from not changing the database extension in your settings file. You don't technically need to create a new database using the spatial template, you can simply run the PostGIS scripts on your existing database to get all of the geospatial goodies. As always, you should backup your existing database before doing this though.
I'm not 100%, but I think that you can pipe postgis.sql and spatial_ref_sys.sql into your existing database, grant permissions to the tables, and change the db setting to "django.contrib.gis.db.backends.postgis". (After you have installed the deps of course)
https://docs.djangoproject.com/en/dev/ref/contrib/gis/install/#spatialdb-template
I'd be interested to see what you find. Be careful, postgis installation can build some character but you don't want it to build too much.
From the docs (django 3.1) https://docs.djangoproject.com/en/3.1/ref/databases/#migration-operation-for-adding-extensions :
If you need to add a PostgreSQL extension (like hstore, postgis, etc.) using a migration, use the CreateExtension operation.
I have to add a new column and a new table to my database but i dont have access to shell of my server. I changed my YAML file. How can i tell doctrine to "migrate models and database to changed yaml"?
Doctrine_Core class has a lot of static methods like generateMigrationsFromDiff(), which you can use in case you dont't have access to cli tasks (see full api at http://www.doctrine-project.org/Doctrine_Core/1_2). I am not sure that it's exactly what you need, so don't forget to make backup :)
I'd like to know your approach/experiences when it's time to initially populate the Grails DB that will hold your app data. Assuming you have CSVs with data, is is "safer" to create a script (with whatever tool fits you) that:
1.-Generates the Bootstrap commands with the domain classes, run it in test or dev environment and then use the native db commands to export it to prod?
2.-Create the DB's insert script assuming GORM's version = 0 and incrementing manually the soon-to-be autogenerated IDs ?
My fear is that the second approach may lead to inconsistencies for hibernate will have the responsability for the IDs generation and there may be something else I'm missing.
Thanks in advance.
Take a look at this link. This allows you to run groovy scripts in the normal grails context giving you access to all grails features including GORM. I'm currently importing data from a legacy database and have found that writing a Groovy script using the Groovy SQL interface to pull out the data then putting that data in domain objects appears to be the easiest thing to do. Once you have the data imported you just use the commands specific to your database system to move that data to the production database.
Update:
Apparently the updated entry referenced from the blog entry I link to no longer exists. I was able to get this working using code at the following link which is also referenced in the comments.
http://pastie.org/180868
Finally it seems that the simplest solution is to consider that GORM as of the current release (1.2) uses a single sequence for all auto-generated ids. So considering this when creating whatever scripts you need (in the language of your preference) should suffice. I understand it's planned for 1.3 release that every table has its own sequence.
Is there any way to add a SQL Server Database Diagram to source control? I can't seem to find a way to script it out of the database. If so, is there a way to get that diagram into a Visual Studio Database Project for easy deployment?
to script it to a file try:
http://www.codeproject.com/KB/database/ScriptDiagram2005.aspx
I would not do this.
I've been allowed to publish my variation on a set of scripts that do just that, providing easy two-way import/export between files and diagrams stored in a database.
https://github.com/timabell/database-diagram-scm
Just run the batch file, pointing at your database of choice and you'll get a set of files, one for each diagram. Unfortunately the data is still binary, but it's a start.
It builds on what others have already done, definitely a shoulders of giants job. :-)
I don't know what the advantage of storing the diagram in source control would be. The database diagrams put an illustration to your database relationships which should be defined elsewhere. So long as you put the creation scripts for your DB in source safe, the diagram should render just fine when you create it and add your tables to it.
There isn't really an easy way of doing this. I typically do one of a few things for this.
Simply print the document to PDF using something like CutePDF
Use Visio and the Reverse Engineering option to generate the document, then save the visio file
Use Enterprise Architect or similar tool for the process.
I personally use option 3, due to the lifecycle that I take my applications through. But the real thing is what are you looking to store, if it is a static version of the database diagram, any of the above are valid.