Working with Databases — Data Model
New Database
As the top-level entity in the API, new databases can be created using the Database class by passing in a name, configuration, or both.
The following example creates a database using the Database(string name) method.
var db = new Database("my-database");Just as before, the database will be created in a default location.
Alternatively, the Database(string name, DatabaseConfiguration config) initializer can be used to provide specific options in the DatabaseConfiguration object such as the database directory.
Database Encryption
| This is an Enterprise Edition feature. |
Couchbase Lite on C#.Net includes the ability to encrypt Couchbase Lite databases. This allows mobile applications to secure the data at rest, when it is being stored on the device. The algorithm used to encrypt the database is 256-bit AES.
To enable encryption, you must set the DatabaseConfiguration.encryptionKey property to the encryption key of your choice.
Provide this encryption key every time the database is opened.
// Create a new, or open an existing database with encryption enabled
var config = new DatabaseConfiguration
{
// Or, derive a key yourself and pass a byte array of the proper size
EncryptionKey = new EncryptionKey("password")
};
using (var db = new Database("seekrit", config)) {
// Change the encryption key (or add encryption if the DB is unencrypted)
db.ChangeEncryptionKey(new EncryptionKey("betterpassw0rd"));
// Remove encryption
db.ChangeEncryptionKey(null);
}Couchbase Lite does not persist the key. It is the application’s responsibility to manage the key and store it in a platform specific secure store such as Apple’s Keychain or Android’s Keystore.
An encrypted database can only be opened with the same language SDK that was used to encrypt it in the first place (Swift, C#, Java, Java (Android) or Objective-C). For example, if a database is encrypted with the Swift SDK and then exported, it will only be readable with the Swift SDK.
Upgrading from 1.x when Encryption is Enabled
If you’re migrating an application from Couchbase Lite 1.x to 2.x, note that the automatic database upgrade functionality is not supported for encrypted databases. Thus, to upgrade an encrypted 1.x database, you should do the following:
-
Disable encryption using the Couchbase Lite 1.x framework (see 1.x encryption guide)
-
Open the database file with encryption enabled using the Couchbase Lite 2.x framework.
Since it is not possible to package Couchbase Lite 1.x and Couchbase Lite 2.x in the same application this upgrade path would require two successive upgrades. If you are using Sync Gateway to synchronize the database content, it may be preferable to run a pull replication from a new 2.x database with encryption enabled and delete the 1.x local database.
Finding a Database File
Where a database goes by default depends on the platform it is running on. Here are the defaults for each platform:
-
.NET Core:
Path.Combine(AppContext.BaseDirectory, "CouchbaseLite")(unless the app context is altered [e.g. by XUnit], this will be the same directory as the output binary) -
UWP:
Windows.Storage.ApplicationData.Current.LocalFolder.Path(Inside the installed app sandbox. Note that this sandbox gets deleted sometimes when debugging from inside Visual Studio when the app is shutdown) -
Xamarin iOS: In a folder named CouchbaseLite inside of
ApplicationSupportDirectory(this can be retrieved more easily from the simulator using the SimPholders utility) -
Xamarin csharp: Using the
Contextpassed in theActivate()method,Context.FilesDir.AbsolutePath(database can be retrieved using adb)
CLI tool
cblite is a command-line tool for inspecting and querying Couchbase Lite 2.x databases.
You can download and build it from the couchbaselabs GitHub repository.
Note that the cblite tool is not supported by the Couchbase Support Policy.
Logging
If you are using a Couchbase Lite release prior to 2.5 see Deprecated functionality
Unresolved include directive in modules/csharp/pages/learn/csharp-database.adoc - include::partial$logging.adoc[]
Logging functionality prior to Release 2.5
|
Deprecation
The pre-Couchbase Lite 2.5 logging functionality is deprecated.
It was superseded by an enhanced Logging API in that release.
This information is included for completeness only.
|
The log messages are split into different domains (LogDomains) which can be tuned to different log levels.
The following example enables verbose logging for the replicator and query domains.
Database.SetLogLevel(LogDomain.Replicator, LogLevel.Verbose);
Database.SetLogLevel(LogDomain.Query, LogLevel.Verbose);Database.SetLogLevel(LogDomain.Replicator, LogLevel.Verbose);
Database.SetLogLevel(LogDomain.Query, LogLevel.Verbose);Loading a pre-built database
If your app needs to sync a lot of data initially, but that data is fairly static and won’t change much, it can be a lot more efficient to bundle a database in your application and install it on the first launch. Even if some of the content changes on the server after you create the app, the app’s first pull replication will bring the database up to date.
To use a prebuilt database, you need to set up the database, build the database into your app bundle as a resource, and install the database during the initial launch.
After your app launches, it needs to check whether the database exists.
If the database does not exist, the app should copy it from the app bundle using the Database.Copy(string, DatabaseConfiguration) method as shown below.
// Note: Getting the path to a database is platform-specific. For .NET Core / .NET Framework this
// can be a simple filesystem path. For UWP, you will need to get the path from your assets. For
// iOS you need to get the path from the main bundle. For Android you need to extract it from your
// assets to a temporary directory and then pass that path.
var path = Path.Combine(Environment.CurrentDirectory, "travel-sample.cblite2" + Path.DirectorySeparatorChar);
if (!Database.Exists("travel-sample", null)) {
_NeedsExtraDocs = true;
Database.Copy(path, "travel-sample", null);
}