C# Sqlite 本地存储

1. download sqlite dll from: http://www.sqlite.org/download.html
windows 版本:

http://www.sqlite.org/2016/sqlite-dll-win32-x86-3130000.zip

2. 拷贝 sqlite3.dll 到 bin 目录

3. 安装nuget： Install-Package sqlite-net
安装后会在项目中找到SQLite.CS和SQLiteAsync.cs

4. demo 代码：

4.1 创建一个抽象的base model ：

public abstract class BaseModel
{
[PrimaryKey]
public Guid Id { get; set; }

protected BaseModel()
{
Id = Guid.NewGuid();
}
}

4.2 测试model

public class Book : BaseModel
{
public Book()
{

}
public Book(string title, string author, int pages)
:base()
{
Title = title;
Author = author;
Pages = pages;
}
public string Title { get; set; }

public int Pages { get; set; }

public string Author { get; set; }

public override string ToString()
{
return string.Format("ID : {0} ,title : {1}, Author : {2}, Pages : {3}", Id, Title, Author, Pages);
}
}

4.3 创建helper class

    

public class SqliteHelper
{
private const string DBPath = "Book.db";
private const int OPERATION_SUCCESS = 1;

public static bool TryDropTable<T>()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var success = db.DropTable<T>();
if (success != OPERATION_SUCCESS)
{
// TODO log error
}

return success == OPERATION_SUCCESS;
}
}

public static bool TryCreateTable<T>()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var table = db.GetTableInfo(typeof (T).Name);
if(table != null && table.Count > 0)
{
return false;
}
db.CreateTable<T>();
return true;
}
}

public static T Add<T>(T book)
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var success = db.Insert(book);
if (success != OPERATION_SUCCESS)
{
//TODO error log
}
}
return book;
}

public static T DeleteById<T>(Guid id) where T : BaseModel, new()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var record = db.Table<T>().FirstOrDefault(x => x.Id == id);
if (record != null)
{
var success = db.Delete(record);
if (success != OPERATION_SUCCESS)
{
// TODO error log
return null;
}
return record;
}
else
{
// TODO log : failed to find record with id 'XXX'
return null;
}
}
}

public static T UpdateById<T>(Guid id, T updating) where T: BaseModel, new ()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var singleRecord = db.Table<T>().FirstOrDefault(x => x.Id == id);
if (singleRecord != null)
{
singleRecord = updating;
singleRecord.Id = id; //restore the id

var success = db.Update(singleRecord);
if (success != OPERATION_SUCCESS)
{
// TODO error log
return null;
}
return updating;
}
else
{
// TODO log  failed to find record with id 'XXX'
return null;
}
}
}

public static T UpdateBy<T>(Expression<Func<T, bool>> where, T updating) where T:BaseModel, new ()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
var records = db.Table<T>().Where(where).ToList();
if (records.Count > 0)
{
for (int i = 0; i < records.Count; i++)
{
var id = records[i].Id;
records[i] = updating;
records[i].Id = id; // restore id
}
var success = db.UpdateAll(records);
if (success != OPERATION_SUCCESS)
{
//TODO error log here
return null;
}
return updating;
}
return null;
}
}

public static IEnumerable<T> All<T>() where T: new()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
return db.Table<T>().ToList();
}
}

public static IEnumerable<T> GetBy<T>(Expression<Func<T, bool>> prediction) where T: new()
{
using (var db = new SQLite.SQLiteConnection(DBPath))
{
return Enumerable.ToList(db.Table<T>().Where(prediction));
}
}
}

5. 使用过程
class Program
{
static void Main(string[] args)
{
SqliteHelper.TryDropTable<Book>();

// create a table
var createResult = SqliteHelper.TryCreateTable<Book>();
Console.WriteLine("First time creating table 'Book' result : " +createResult);

// try create it again
createResult = SqliteHelper.TryCreateTable<Book>();
Console.WriteLine("2nd time creating table 'Book' result : " + createResult);

// try add record
var firstRecord = SqliteHelper.Add(new Book("first", "aaa", 100));
Console.WriteLine("first book added :");
Console.WriteLine(firstRecord);
// try update by id
var updatedFirst = SqliteHelper.UpdateById(firstRecord.Id, new Book("updated first", "aaa_updated", 101));
Console.WriteLine("updated first record:");
Console.WriteLine(updatedFirst);

// add another record
var secondRecord = SqliteHelper.Add(new Book("second", "bbb", 200));
Console.WriteLine("2nd book added :");
Console.WriteLine(secondRecord);

// try update by
var updatedSecond = SqliteHelper.UpdateBy(
x=> x.Title == secondRecord.Title && x.Author == secondRecord.Author,
new Book("updated 2nd", "bbb_updated", 201));

Console.WriteLine("updated 2nd record:");
Console.WriteLine(updatedSecond);

// try delete first
var deleted = SqliteHelper.DeleteById<Book>(firstRecord.Id);
Console.WriteLine("First record deleted.");

// All records :
Console.WriteLine("all records :");
var all = SqliteHelper.All<Book>();
foreach (var record in all)
{
Console.WriteLine(record);
}

Console.ReadKey();
}
}