程序師世界是廣大編程愛好者互助、分享、學習的平台,程序師世界有你更精彩!
首頁
編程語言
C語言|JAVA編程
Python編程
網頁編程
ASP編程|PHP編程
JSP編程
數據庫知識
MYSQL數據庫|SqlServer數據庫
Oracle數據庫|DB2數據庫
 程式師世界 >> 編程語言 >> .NET網頁編程 >> C# >> C#基礎知識 >> C#/Java連接sqlite與使用技巧

C#/Java連接sqlite與使用技巧

編輯:C#基礎知識

1)下載sqlite jdbc驅動http://www.xerial.org/maven/repository/artifact/org/xerial/sqlite-jdbc/

2)將下載的驅動加入eclipse項目的built path中

3)示例代碼:

代碼如下:

package com.hedalixin;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;

public class test {

    /**
     * @param args
     */
    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        Class.forName("org.sqlite.JDBC");
        Connection conn = DriverManager.getConnection("jdbc:sqlite:test.db");
        Statement stat = conn.createStatement();
        stat.executeUpdate("drop table if exists people;");
        stat.executeUpdate("create table people (name, occupation);");
        PreparedStatement prep = conn
                .prepareStatement("insert into people values (?, ?);");

        prep.setString(1, "Gandhi");
        prep.setString(2, "politics");
        prep.addBatch();
        prep.setString(1, "Turing");
        prep.setString(2, "computers");
        prep.addBatch();
        prep.setString(1, "Wittgenstein");
        prep.setString(2, "smartypants");
        prep.addBatch();
        conn.setAutoCommit(false);
        prep.executeBatch();
        conn.setAutoCommit(true);
        ResultSet rs = stat.executeQuery("select * from people;");
        while (rs.next()) {
            System.out.println("name = " + rs.getString("name"));
            System.out.println("job = " + rs.getString("occupation"));
        }
        rs.close();
        conn.close();

    }
}

2.  C#連接sqlite
2.1 使用SQLITE.NET
SQLite.NET也是一個數據訪問組件,其中的System.Data.SQLite 就好像是.NET自帶的System.Data.SqlClient一樣。裡面包含了connection、command等數據訪問的常用對象,只是他們前面都有一個前綴sqlite。
1)下載System.Data.SQLite,下載地址http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki

2)  通過Add References引用SQLite ADO .NET安裝目錄的bin目錄下的System.Data.SQLite.DLL。

3)創建表、讀取數據等和Access或MS SQL沒多大區別

代碼如下:

//創建一個數據庫文件
string datasource="h:/test.db";
System.Data.SQLite.SQLiteConnection.CreateFile(datasource);
//連接數據庫
System.Data.SQLite.SQLiteConnection conn = new System.Data.SQLite.SQLiteConnection();
System.Data.SQLite.SQLiteConnectionStringBuilder connstr = new System.Data.SQLite.SQLiteConnectionStringBuilder();
connstr.DataSource = datasource;
connstr.Password = "admin";//設置密碼,SQLite ADO.NET實現了數據庫密碼保護
conn.ConnectionString = connstr.ToString();            
conn.Open();
//創建表
System.Data.SQLite.SQLiteCommand cmd = new System.Data.SQLite.SQLiteCommand();
string sql = "CREATE TABLE test(username varchar(20),password varchar(20))";
cmd.CommandText=sql;
cmd.Connection=conn;
cmd.ExecuteNonQuery();
//插入數據
sql = "INSERT INTO test VALUES('ekinglong','mypassword')";
cmd.CommandText = sql;
cmd.ExecuteNonQuery();
//取出數據
sql = "SELECT * FROM test";
cmd.CommandText = sql;
System.Data.SQLite.SQLiteDataReader reader = cmd.ExecuteReader();
StringBuilder sb = new StringBuilder();
while (reader.Read())
{
     sb.Append("username:").Append(reader.GetString(0)).Append("\n")
     .Append("password:").Append(reader.GetString(1));

 }
 MessageBox.Show(sb.ToString());

2.2使用原生態的ADO.NET訪問SQLite

代碼如下:

using (DbConnection conn = new SQLiteConnection( System.Configuration.ConfigurationManager.ConnectionStrings["sqlite"].ConnectionString))
{
    conn.Open();
    DbCommand comm = conn.CreateCommand();
    comm.CommandText = "select * from customer";
    comm.CommandType = CommandType.Text;
    using (IDataReader reader = comm.ExecuteReader())
    {
        while (reader.Read())
        {
            Response.Write(reader[0]);
        }
    }
}

SQLite.NET數據庫連接字符串ConnectionString格式:
Basic(基本的)
      Data Source=filename;Version=3;
Using UTF16(使用UTF16編碼)
      Data Source=filename;Version=3;UseUTF16Encoding=True;
With password(帶密碼的)
      Data Source=filename;Version=3;Password=myPassword;
Using the pre 3.3x database format(使用3.3x前數據庫格式)
      Data Source=filename;Version=3;Legacy Format=True;
Read only connection(只讀連接)
      Data Source=filename;Version=3;Read Only=True;
With connection pooling(設置連接池)
      Data Source=filename;Version=3;Pooling=False;Max Pool Size=100;
Using DateTime.Ticks as datetime format()
      Data Source=filename;Version=3;DateTimeFormat=Ticks;
      The default value is ISO8601 which activates the use of the ISO8601 datetime format
Store GUID as text(把Guid作為文本存儲,默認是Binary)
     Data Source=filename;Version=3;BinaryGUID=False;
      如果把Guid作為文本存儲需要更多的存儲空間
Specify cache size(指定Cache大小)
      Data Source=filename;Version=3;Cache Size=2000;
      Cache Size 單位是字節
Specify page size(指定頁大小)
      Data Source=filename;Version=3;Page Size=1024;
      Page Size 單位是字節
Disable enlistment in distributed transactions
      Data Source=filename;Version=3;Enlist=N;
Disable create database behaviour(禁用創建數據庫行為)
      Data Source=filename;Version=3;FailIfMissing=True;
      默認情況下,如果數據庫文件不存在,會自動創建一個新的,使用這個參數,將不會創建,而是拋出異常信息
Limit the size of database(限制數據庫大小)
      Data Source=filename;Version=3;Max Page Count=5000;
      The Max Page Count is measured in pages. This parameter limits the maximum number of pages of the database.
Disable the Journal File (禁用日志回滾)
      Data Source=filename;Version=3;Journal Mode=Off;
      This one disables the rollback journal entirely.
Persist the Journal File(持久)
      Data Source=filename;Version=3;Journal Mode=Persist;
      This one blanks and leaves the journal file on disk after a commit. Default behaviour is to delete the Journal File after each commit.
Controling file flushing
      Data Source=filename;Version=3;Synchronous=Full;
      Full specifies a full flush to take action after each write. Normal is the default value. Off means that the underlying OS flushes I/O's.

Sqlite使用技巧
1 .Sqlite判斷數據表是否存在
SELECT COUNT(*)  as CNT FROM sqlite_master where type='table' and name='DBInfo' //其中DBInfo為需要判斷的表名。注意大小寫敏感!

2. SQLite一條SQL語句插入多條記錄
INSERT INTO TABLE(col1, col2) SELECT val11, val12 UNION ALL SELECT val21, val22 ;
這樣的寫法是屬於復合SQL語句,表示先把兩個SELECT的結果集進行無刪減的聯合,再把聯合結果插入到TABLE中。

3. sqlite事務
是以文件的形式存在磁盤中,每次訪問時都要打開一次文件,如果對數據進行大量操作時,會很慢~
解決辦法是用事務的形式提交:因為我們開始事務後,進行大量操作的語句都保存在內存中,當提交時才全部寫入數據庫,此時,數據庫文件也就只用打開一次。
sql語句:
begin;  
INSERT INTO "table" VALUES ('a', 'b', 'c');  
INSERT INTO "table" VALUES ('a', 'b', 'c');  
INSERT INTO "table" VALUES ('a', 'b', 'c');  
commit;
4. SQLite自增ID字段使用方法為      INTEGER PRIMARY KEY AUTOINCREMENT
5. 分頁查詢顯示
類似MySQL數據庫 ,是利用mySQL的LIMIT函數,LIMIT [offset,] rows從數據庫表中M條記錄開始檢索N條記錄的語句為:
SELECT * FROM 表名稱 LIMIT M,N
例如從表Sys_option(主鍵為sys_id)中從10條記錄開始檢索20條記錄,語句如下:
select * from sys_option limit 10,20

  1. 上一頁:
  2. 下一頁:
Copyright © 程式師世界 All Rights Reserved