Note: In contrast to ISO 8601 SQLite doesn't offer any timezone support.Īlso missing is a boolean type. Stored this way SQLite offers some date/time functions to add days, change to the start of the month and things like that. Together with the publishing time it would look like this: " T07:58". The string to represent the 28th of March 2013 (the day of publishing this post) would be " ". The best thing to do is to store dates as Strings in the ISO 8601 format. The biggest problem here is the missing datetime type. double precision)Īny String and also single characters (UTF-8, UTF-16BE or UTF-16LE) SQLite datatypes TypeĪny number which is no floating point numberįloating-point numbers (8-Byte IEEE 754 - i.e. If you use other types (like varchar) in your CREATE TABLE statement SQLite maps them as closely as possible to any of these types. The following table shows all types supported by SQLite. Newer versions add a journal file which is used during transactions. This file contains the main data, as well as indices, triggers and any meta data needed by SQLite itself. SQLite uses one file to store all the contents of your database. All data is stored in one single database file I will cover how to create a database in the next part of this tutorial series. You simply create the database files when you need it. No port configuration, no adding of users, no managing of access levels, no tablespace setup and what not. You do not need to configure the database in any way. You use SQLite more like a library which helps you to access the database files. There is no SQLite process running at all. I will delve into each of these points a bit deeper - and add another one that's only relevant if you want to support older Android versions. SQLite uses cross-platform database files.SQLite uses manifest typing instead of static types.SQLite stores data in one database file.Though SQLite offers quite an impressive feature set given its size, it differs in many aspects from a conventional database system: Android for example uses ever newer versions in its SDKs to make use of these improvements. The project is maintained actively so one can expect further imrpovements as well as optimizations in the future. And it is used in many, many products and open source projects. SQLite has a huge commercial backing by the likes of Google, Adobe, Mozilla or Bloomberg. SQLite's source code is released under the public domain Those systems must run out of the box without forcing the user to manually configure anything or forcing the developers to consider additional constraints. You definitely do do not want these on mobile systems. No need for configuration files or complicated commands. I will detail what this means in the next section, but it makes handling of the database that much easier. Gladly SQLite should not add too much burden to the memory consumption of your app. Keep in mind: In the mobile world the memory per process as well as total usage of memory is limited compared to desktop systems. While SQLite's memory footprint starts at about 50 kilobyte it's remains low even for bigger projects with more complex data structures (at about a few hundred kilobytes). SQLite in Android consumes very little memory Of course there is a reason why SQLite is so dominant in the embedded and also the mobile world. This database was developed with embedded environments in mind - and is used not only by Android but also by Apple's iOS and Blackberry's system as well as lots of other systems with low memory footprint and comparatively little CPU horsepower. Private static class DatabaseHelper extends SQLiteOpenHelper ,īyte blob = cur.getBlob(cur.SQLite is at the heart of Android's database support. IMAGE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " "CREATE TABLE IF NOT EXISTS " + IMAGES_TABLE + " (" + Private static final String CREATE_IMAGES_TABLE = Private static final String IMAGES_TABLE = "ImagesTable" Private static final int DATABASE_VERSION = 1 Private static final String DATABASE_NAME = "Images.db" Public static final String IMAGE = "image" Public static final String IMAGE_ID = "id" We are going to save our selected image in the column “image”. Note : If you want to see the SQLite DB Structure and values in Eclipse you can check this post. Our Database contains only one table “Images” with two columns “id” and “image”. First I will just create a Database Helper Class for adding and reading from the Database.
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