The SQLite.NET library that Xamarin recommends is a very basic ORM thatlets you easily store and retrieve objects in the local SQLite databaseon an Android device. ORM stands for Object Relational Mapping – anAPI that lets you save and retrieve 'objects' from a databasewithout writing SQL statements.
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Apr 26, 2019 Enable root shell on your nook glowlight plus. Connect your nook to your PC with a USB cable. Launch a command line and change into the directory where you extracted the Android SDK. Run 'adb devices' and make sure your nook is showing up as a device. This article talks about connecting with SQLite database, create database, create table, insert records in tables and display records from table in an Android application. Why Join Become a. Each entry in most SQLite tables (except for WITHOUT ROWID tables) has a unique 64-bit signed integer key called the 'rowid'. The rowid is always available as an undeclared column named ROWID, OID, or ROWID as long as those names are not also used by explicitly declared columns.
To include the SQLite.NET library in a Xamarin app, add the following NuGet package to your project:
Tip
There are a number of different SQLite packages available – be sure to choose the correct one (it might not be the top result in search).
Android Sqlite Library
Once you have the SQLite.NET library available, follow these three steps to use it to access a database:
Basic Data Access Sample
The DataAccess_Basic sample code for this document looks like thiswhen running on Android. The code illustrates how to perform simpleSQLite.NET operations and shows the results in as text in theapplication's main window.
Android
The following code sample shows an entire database interaction usingthe SQLite.NET library to encapsulate the underlying database access.It shows:
You'll need to include these namespaces:
The last one requires that you have added SQLite to your project. Notethat the SQLite database table is defined by adding attributes to aclass (the
Stock class) rather than a CREATE TABLE command.
Using the
[Table] attribute without specifying a table name parameterwill cause the underlying database table to have the same name as theclass (in this case, 'Stock'). The actual table name is importantif you write SQL queries directly against the database rather than usethe ORM data access methods. Similarly the [Column('_id')] attributeis optional, and if absent a column will be added to the table with thesame name as the property in the class.
SQLite Attributes
Common attributes that you can apply to your classes to control howthey are stored in the underlying database include:
Most of these attributes are optional. You should always specify an integerprimary key so that selection and deletion queries can be performedefficiently on your data.
More Complex Queries
The following methods on
SQLiteConnection can be used to perform other data operations:
Getting an object by the primary key
SQLite.Net provides the Get method to retrieve a single object based on its primary key.
Selecting an object using Linq
Methods that return collections support
IEnumerable<T> so you can useLinq to query or sort the contents of a table. The following code showsan example using Linq to filter out all entries that begin with theletter 'A':
Selecting an object using SQL
Even though SQLite.Net can provide object-based access to your data,sometimes you might need to do a more complex query than Linq allows(or you may need faster performance). You can use SQL commands with theQuery method, as shown here:
Note
When writing SQL statements directly you create adependency on the names of tables and columns in your database, whichhave been generated from your classes and their attributes. If youchange those names in your code you must remember to update anymanually written SQL statements.
Deleting an object
The primary key is used to delete the row, as shown here:
You can check the
rowcount to confirm how many rows were affected(deleted in this case).
Using SQLite.NET with Multiple Threads
SQLite supports three different threading modes: Single-thread,Multi-thread, and Serialized. If you want to access the databasefrom multiple threads without any restrictions, you can configureSQLite to use the Serialized threading mode. It's important to setthis mode early in your application (for example, at the beginning ofthe
OnCreate method).
To change the threading mode, call
SqliteConnection.SetConfig . Forexample, this line of code configures SQLite for Serialized mode:
The Android version of SQLite has a limitation that requires a few moresteps. If the call to
SqliteConnection.SetConfig produces a SQLiteexception such as library used incorrectly , then you must use thefollowing workaround:
This workaround also works for the
Mono.Data.Sqlite library. For moreinformation about SQLite and multi-threading, seeSQLite and Multiple Threads.
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To include the SQLite.NET library in a Xamarin app, add the following NuGet package to your project:
Tip
There are a number of different SQLite packages available – be sure to choose the correct one (it might not be the top result in search).
Once you have the SQLite.NET library available, follow these three steps to use it to access a database:
![]() Basic Data Access Sample
The DataAccess_Basic sample code for this document looks like thiswhen running on Android. The code illustrates how to perform simpleSQLite.NET operations and shows the results in as text in theapplication's main window.
Android
The following code sample shows an entire database interaction usingthe SQLite.NET library to encapsulate the underlying database access.It shows:
You'll need to include these namespaces:
The last one requires that you have added SQLite to your project. Notethat the SQLite database table is defined by adding attributes to aclass (the
Stock class) rather than a CREATE TABLE command.
Using the
[Table] attribute without specifying a table name parameterwill cause the underlying database table to have the same name as theclass (in this case, 'Stock'). The actual table name is importantif you write SQL queries directly against the database rather than usethe ORM data access methods. Similarly the [Column('_id')] attributeis optional, and if absent a column will be added to the table with thesame name as the property in the class.
SQLite Attributes
Common attributes that you can apply to your classes to control howthey are stored in the underlying database include:
![]()
Most of these attributes are optional. You should always specify an integerprimary key so that selection and deletion queries can be performedefficiently on your data.
More Complex Queries
The following methods on
SQLiteConnection can be used to perform other data operations:
Sqlite Get Primary KeyGetting an object by the primary key
SQLite.Net provides the Get method to retrieve a single object based on its primary key.
Selecting an object using Linq
Methods that return collections support
IEnumerable<T> so you can useLinq to query or sort the contents of a table. The following code showsan example using Linq to filter out all entries that begin with theletter 'A':
Selecting an object using SQL
Even though SQLite.Net can provide object-based access to your data,sometimes you might need to do a more complex query than Linq allows(or you may need faster performance). You can use SQL commands with theQuery method, as shown here:
Note
When writing SQL statements directly you create adependency on the names of tables and columns in your database, whichhave been generated from your classes and their attributes. If youchange those names in your code you must remember to update anymanually written SQL statements.
Get Generated Key Sqlite Android PhoneDeleting an object
The primary key is used to delete the row, as shown here:
You can check the
rowcount to confirm how many rows were affected(deleted in this case).
Using SQLite.NET with Multiple Threads
SQLite supports three different threading modes: Single-thread,Multi-thread, and Serialized. If you want to access the databasefrom multiple threads without any restrictions, you can configureSQLite to use the Serialized threading mode. It's important to setthis mode early in your application (for example, at the beginning ofthe
OnCreate method).
To change the threading mode, call
SqliteConnection.SetConfig . Forexample, this line of code configures SQLite for Serialized mode:
The Android version of SQLite has a limitation that requires a few moresteps. If the call to
SqliteConnection.SetConfig produces a SQLiteexception such as library used incorrectly , then you must use thefollowing workaround:
This workaround also works for the
Mono.Data.Sqlite library. For moreinformation about SQLite and multi-threading, seeSQLite and Multiple Threads.
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