10 wp7 local database

Windows Phone 7
Li Jingnan / Wang Tao
2011-7-15
1

2 days
2

ethos
http://www.ethostechnologies.com/
One of the 1st ISVs for cloud computing in Europe and China.
Cloud computing development partner with Microsoft in Greater China Region.
Invited to speak about Azure at several Microsoft events.

about
anytao| Ethos
<ethos:Member
id = “Wang Tao”
msn = anytao@live.com
weibo = http://weibo.com/anytao
runat = “Senior System Architect”
/>
Jason | Ethos
<ethos:Member
id = “Li Jingnan”
msn = zengnami@hotmail.com
weibo= http://weibo.com/jn1981
runat = “SE”
/>

about
http://book.anytao.net

10 Local Database
Wang Tao / 2011-07-15

session outline
LINQ to SQL
LINQ to User Data
overview
architecture
code-first development
implementation details
queries
inserts, updates, deletes…
database schema upgrades
performance and best practices
overview
end-user consent
supported account types
implementation details
querying contacts
querying appointments

LINQ to everything
LINQ
Objects
XML
SQL
User Data
OData
7
Mango

complex schema
numerous relationships and constraints
example: shopping list
7 tables
100s of records
5 foreign keys

Reference Data
Huge amounts of static reference data
Example: dictionary app
3 tables
1 table with 500k rows

web service cache
Cloud Service
fetch reference data from cloud
cache it locally
combine with user-specific data
Windows Phone
Service Cache
User Data

user data
filter contacts
birthdays in the next month
query all appointments
find an available time for a meeting
Filter

database support

local data storage: overview
apps store private data in Isolated Storage
settings and properties in the app dictionary
unstructured data in Isolated Storage files
structured data in database files
App Root Folder
Install
Package Manager
Creates root folder
sandboxed to App
DB
Database
File (r/o)
App Data Folder
Creates/Manages
files and settings
App
WP7 Isolated Storage APIs
DB
Application
Settings File
Application
Files
Database file

architecture
Your App
Custom Data Context
App Objects
var query = fromw indb.Wines
wherew.Country== “USA"
selectw.Name;
System.Data.Linq
Identity Management
Change Tracking
Update Processing
Object Materialization
.Call System.Linq.Queryable.Select( .Call System.Linq.Queryable.Where( .Constant(Table(Wines)), '(.Lambda #Lambda1)), '(.Lambda #Lambda2)) .Lambda #Lambda1(db.Wines $w) { $w.Country== “USA" } .Lambda #Lambda2(w.Country $w) { $w.Name}
select Name
from Wines
where Country = “USA”
Microsoft.Phone.Data.Internal
Core ADO.NET (System.Data)
SQL CE DB
SQLCE ADO.NET Provider (System.Data.SqlServerCe)

code first development
Design time
Create object model: wines, varietals, vineyards, etc.
Decorate objects with attributes for persistence
Varietals
Wines
Vineyards
WineMakers
Create DataContextreference to database
Translate object model into a database file
Submit API persists changes to DB
Run time
Database upgrade
Create new objects to enable new features
Use upgrade APIs to change DB

database creation: example
// Define the data context.
publicpartialclassWineDataContext: DataContext
{
publicTable<Wine> Wines;
publicTable<Vineyard> Vineyards;
publicWineDataContext(stringconnection) : base(connection) { }
}
// Define the tables in the database
[Table]
publicclassWine
{
[Column(IsPrimaryKey=true]
publicstringWineID{ get; set; }
[Column]
publicstringName { get; set; }
……
}
// Create the database form data context, using a connection string
DataContextdb = newWineDataContext("isostore:/wineDB.sdf");
if (!db.DatabaseExists()) db.CreateDatabase();

queries: examples
// Create the database form data context, using a connection string
DataContextdb = newWineDataContext("isostore:/wineDB.sdf");
// Find all wines currently at home, ordered by date acquired
varq = from w indb.Wines
wherew.Varietal.Name == “Shiraz” && w.IsAtHome == true
orderbyw.DateAcquired
select w;

Inserts/Updates/Deletes
Your App Code
It’s all about the DataContext
Changes made against the DataContext first
Changes persisted by calling SubmitChanges()
SubmitChanges
LINQ to SQL determines change set and submits to DB
DataContext
DB

inserts/updates/deletes
update
insert
WinenewWine= newWine
{
WineID= “1768",
Name = “Windows Phone Syrah",
Description = “Bold and spicy"
};
db.Wines.InsertOnSubmit(newWine);
db.SubmitChanges();
Winewine=
(fromw indb.Wines
wherew.WineID== “1768"
select w).First();
wine.Description= “Hints of plum and melon";
db.SubmitChanges();

delete
varvineyardsToDelete=
fromVineyards v in db.Vineyards
wherev.Country== “Australia”
select v;
db.Vineyards.DeleteAllOnSubmit
(vineyardsToDelete);
db.SubmitChanges();
Foreign key constraint will cause exception here if Wines associated with the Vineyards are not deleted first

varvineyardsToDelete= fromVineyards v indb.Vineyards
wherev.Country== “Australia"
select v;
foreach (Vineyards v invineyardsToDelete)
{
db.Wines.DeleteAllOnSubmit(v.Wines);
}
db.Vineyards.DeleteAllOnSubmit(vineyardsToDelete);
db.SubmitChanges();

database schema upgrades
DatabaseSchemaUpdater allows for simple upgrades on your existing DB
It offers the ability to add
Tables
Columns
Indices
Associations/foreign keys
All schema updates are transactional
More complex schema upgrades require full DB migration

Database Schema Upgrades
Create a new DatabaseSchemaUpdater
MyDerivedDataContext context = newMyDerivedDataContext("foo.sdf");DatabaseSchemaUpdaterdbUpdater = context.CreateDatabaseSchemaUpdater();
Add a new table tied to the Product class
dbUpdater.AddTable<Winemaker>();
Add a Region column to the Customer table
dbUpdater.AddColumn<Vineyard>(“YearEstablished");
Execute upgrade
dbUpdater.Execute();

keep change sets small
Submit early and often to avoid data loss on app termination
use background threads
Non-trivial operations will impact app responsiveness if done on UI thread
optimize read-only queries
Set ObjectTrackingEnabled to minimize memory usage
use secondary indices for properties which you query often

populate large reference data tables in advance
Create a simple project to prepopulate data in emulator
Pull out database file using Isolated Storage explorer
when to use a database…
expect some impact to startup time and memory usage from incorporating a DB
stick to IsolatedStorageSettings or basic files for small data sets

user data

new and updated APIs in “Mango”
Chooser Tasks related to user data
EmailAddressChooserTask
PhoneNumberChooserTask
AddressChooserTask
Microsoft.Phone.UserData for direct access
Contacts
Appointments

AddressChooserTask
privateAddressChooserTaskaddressChooserTask;
// Constructor
publicMainPage()
{
this.addressChooserTask= newAddressChooserTask();
this.addressChooserTask.Completed += new
EventHandler<AddressResult>(
addressChooserTask_Completed);
}
privatevoidaddressChooserTask_Completed(objectsender, AddressResulte)
{
if(null == e.Error && TaskResult.OK == e.TaskResult)
{
... = e.DisplayName;
... = e.Address;
}
}

Microsoft.Phone.UserData
Important points
Contacts and Appointments APIs are read only
Third party social network data cannot be shared

Contacts/Appointments Data Shared

contacts: hello, world!
Contactscontacts = newContacts();
contacts.SearchCompleted+= newEventHandler<ContactsSearchEventArgs>((sender, e) =>
{
...= e.Results;
});
// E.g. search for all contacts
contacts.SearchAsync(string.Empty, FilterKind.None, null);
state
// E.g. search for all contacts with display name matching "ja"
contacts.SearchAsync("ja", FilterKind.DisplayName, null);
filter expression
(not a regex)
Filter kind: name, email , phone or pinned to start)

appointments: hello, world!
Appointmentsappointments = newAppointments();
appointments.SearchCompleted+= newEventHandler<AppointmentsSearchEventArgs>((sender, e) =>
{
... = e.Results;
});
// E.g. get next appointment (up to 1 week away)
appointments.SearchAsync(DateTime.Now,
DateTime.Now+ TimeSpan.FromDays(7),
1, null);
start date and time
end date and time
Maximum items to return
state

be responsible
your privacy policy should cover how you use the user’s contact information
keep out of the way
users have widely varying contact list sizes
your UI should handle delays gracefully
don’t let data get stale
data returned is a snapshot
refresh state when reasonable

demo
35
/ linq to sql
/ datacontext
/ CRUD
/ user data
04 user manager

practice
36
a todo list

thank you
37
thank youwww.anytao.com

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10 wp7 local database

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10 wp7 local database — Presentation Transcript