SQLite之C#版 System.Data.SQLite使用方法

更新時(shí)間：2020年10月08日 23:48:54 作者：孟棟

這篇文章主要介紹了SQLite之C#版 System.Data.SQLite使用方法,需要的朋友可以參考下

SQLite簡(jiǎn)介

SQLite，是一款輕型的關(guān)系型數(shù)據(jù)庫(kù)。它的設(shè)計(jì)目標(biāo)是嵌入式。

它能夠支持Windows/Linux/Unix等等主流的操作系統(tǒng)，同時(shí)能夠跟很多程序語(yǔ)言相結(jié)合，比如 C++、C#、Object-C、PHP、Java等。

我是做手游開(kāi)發(fā)的，在手機(jī)上使用SQLite 存儲(chǔ)數(shù)據(jù)是很方便的。

System.Data.SqLite實(shí)踐前期準(zhǔn)備

System.Data.SQLite 庫(kù)下載，用于C#操作SQLite的dll文件。下載地址：http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki
SQLite可視化工具下載，用于查看SQLite庫(kù)數(shù)據(jù)表數(shù)據(jù)。下載地址：http://www.sqliteexpert.com/download.html

Tips:

1.根據(jù)自己的電腦是64bit或者32bit 以及使用的.NET Freamwork版本下載相應(yīng)的的System.Data.SQLite。下載解壓文件如：

安裝在指定目錄后生成多個(gè)dll文件：

本文測(cè)試用的只有 System.Data.SQLite.dll 。對(duì)于SQLite庫(kù)數(shù)據(jù)的增刪改查已經(jīng)足夠用了。

2.SQLite數(shù)據(jù)庫(kù)文件以.db為后綴。安裝SQLite可視化工具后如圖：

mydb是我測(cè)試用的數(shù)據(jù)庫(kù)。

實(shí)踐

對(duì)SQLite的增、刪、改、查。

測(cè)試環(huán)境：VS2015 語(yǔ)言：C#

創(chuàng)建控制臺(tái)新工程，引入System.Data.SQLite.dll 文件。

1.編寫(xiě)SQLite 操作類，對(duì)SQLite數(shù)據(jù)操作進(jìn)行封裝為 SqLiteHelper，代碼如下：

/// <summary>
  /// SQLite 操作類
  /// </summary>
  class SqLiteHelper
  {

    /// <summary>
    /// 數(shù)據(jù)庫(kù)連接定義
    /// </summary>
    private SQLiteConnection dbConnection;

    /// <summary>
    /// SQL命令定義
    /// </summary>
    private SQLiteCommand dbCommand;

    /// <summary>
    /// 數(shù)據(jù)讀取定義
    /// </summary>
    private SQLiteDataReader dataReader;

    /// <summary>
    /// 構(gòu)造函數(shù)
    /// </summary>
    /// <param name="connectionString">連接SQLite庫(kù)字符串</param>
    public SqLiteHelper(string connectionString)
    {
      try
      {
        dbConnection = new SQLiteConnection(connectionString);
        dbConnection.Open();
      }catch(Exception e)
      {
        Log(e.ToString());
      }
    }
    /// <summary>
    /// 執(zhí)行SQL命令
    /// </summary>
    /// <returns>The query.</returns>
    /// <param name="queryString">SQL命令字符串</param>
    public SQLiteDataReader ExecuteQuery(string queryString)
    {
      try
      {
        dbCommand = dbConnection.CreateCommand();
        dbCommand.CommandText = queryString;
        dataReader = dbCommand.ExecuteReader();
      }catch(Exception e)
      {
        Log(e.Message);
      }

      return dataReader;
    }
    /// <summary>
    /// 關(guān)閉數(shù)據(jù)庫(kù)連接
    /// </summary>
    public void CloseConnection()
    {
      //銷毀Commend
      if(dbCommand !=null)
      {
        dbCommand.Cancel();
      }
      dbCommand = null;
      //銷毀Reader
      if(dataReader != null)
      {
        dataReader.Close();
      }
      dataReader = null;
      //銷毀Connection
      if(dbConnection != null)
      {
        dbConnection.Close();
      }
      dbConnection = null;

    }

    /// <summary>
    /// 讀取整張數(shù)據(jù)表
    /// </summary>
    /// <returns>The full table.</returns>
    /// <param name="tableName">數(shù)據(jù)表名稱</param>
    public SQLiteDataReader ReadFullTable(string tableName)
    {
      string queryString = "SELECT * FROM " + tableName;
      return ExecuteQuery(queryString);
    }


    /// <summary>
    /// 向指定數(shù)據(jù)表中插入數(shù)據(jù)
    /// </summary>
    /// <returns>The values.</returns>
    /// <param name="tableName">數(shù)據(jù)表名稱</param>
    /// <param name="values">插入的數(shù)值</param>
    public SQLiteDataReader InsertValues(string tableName, string[] values)
    {
      //獲取數(shù)據(jù)表中字段數(shù)目
      int fieldCount = ReadFullTable(tableName).FieldCount;
      //當(dāng)插入的數(shù)據(jù)長(zhǎng)度不等于字段數(shù)目時(shí)引發(fā)異常
      if (values.Length != fieldCount)
      {
        throw new SQLiteException("values.Length!=fieldCount");
      }

      string queryString = "INSERT INTO " + tableName + " VALUES (" + "'"+ values[0]+"'";
      for (int i = 1; i < values.Length; i++)
      {
        queryString += ", " + "'"+values[i] + "'";
      }
      queryString += " )";
      return ExecuteQuery(queryString);
    }

    /// <summary>
    /// 更新指定數(shù)據(jù)表內(nèi)的數(shù)據(jù)
    /// </summary>
    /// <returns>The values.</returns>
    /// <param name="tableName">數(shù)據(jù)表名稱</param>
    /// <param name="colNames">字段名</param>
    /// <param name="colValues">字段名對(duì)應(yīng)的數(shù)據(jù)</param>
    /// <param name="key">關(guān)鍵字</param>
    /// <param name="value">關(guān)鍵字對(duì)應(yīng)的值</param>
    /// <param name="operation">運(yùn)算符：=,<,>,...，默認(rèn)“=”</param>
    public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key, string value, string operation="=")
    {
      //當(dāng)字段名稱和字段數(shù)值不對(duì)應(yīng)時(shí)引發(fā)異常
      if (colNames.Length != colValues.Length)
      {
        throw new SQLiteException("colNames.Length!=colValues.Length");
      }

      string queryString = "UPDATE " + tableName + " SET " + colNames[0] + "=" + "'" + colValues[0] + "'";
      for (int i = 1; i < colValues.Length; i++)
      {
        queryString += ", " + colNames[i] + "=" + "'" + colValues[i] + "'";
      }
      queryString += " WHERE " + key + operation + "'" + value + "'";
      return ExecuteQuery(queryString);
    }

    /// <summary>
    /// 刪除指定數(shù)據(jù)表內(nèi)的數(shù)據(jù)
    /// </summary>
    /// <returns>The values.</returns>
    /// <param name="tableName">數(shù)據(jù)表名稱</param>
    /// <param name="colNames">字段名</param>
    /// <param name="colValues">字段名對(duì)應(yīng)的數(shù)據(jù)</param>
    public SQLiteDataReader DeleteValuesOR(string tableName, string[] colNames, string[] colValues, string[] operations)
    {
      //當(dāng)字段名稱和字段數(shù)值不對(duì)應(yīng)時(shí)引發(fā)異常
      if (colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length)
      {
        throw new SQLiteException("colNames.Length!=colValues.Length || operations.Length!=colNames.Length || operations.Length!=colValues.Length");
      }

      string queryString = "DELETE FROM " + tableName + " WHERE " + colNames[0] + operations[0] + "'" + colValues[0] + "'";
      for (int i = 1; i < colValues.Length; i++)
      {
        queryString += "OR " + colNames[i] + operations[0] + "'" + colValues[i] + "'";
      }
      return ExecuteQuery(queryString);
    }

    /// <summary>
    /// 刪除指定數(shù)據(jù)表內(nèi)的數(shù)據(jù)
    /// </summary>
    /// <returns>The values.</returns>
    /// <param name="tableName">數(shù)據(jù)表名稱</param>
    /// <param name="colNames">字段名</param>
    /// <param name="colValues">字段名對(duì)應(yīng)的數(shù)據(jù)</param>
    public SQLiteDataReader DeleteValuesAND(string tableName, string[] colNames, string[] colValues, string[] operations)
    {
      //當(dāng)字段名稱和字段數(shù)值不對(duì)應(yīng)時(shí)引發(fā)異常
      if (colNames.Length != colValues.Length || operations.Length != colNames.Length || operations.Length != colValues.Length)
      {
        throw new SQLiteException("colNames.Length!=colValues.Length || operations.Length!=colNames.Length || operations.Length!=colValues.Length");
      }

      string queryString = "DELETE FROM " + tableName + " WHERE " + colNames[0] + operations[0] + "'" + colValues[0] + "'";
      for (int i = 1; i < colValues.Length; i++)
      {
        queryString += " AND " + colNames[i] + operations[i] + "'" + colValues[i] + "'";
      }
      return ExecuteQuery(queryString);
    }


    /// <summary>
    /// 創(chuàng)建數(shù)據(jù)表
    /// </summary> +
    /// <returns>The table.</returns>
    /// <param name="tableName">數(shù)據(jù)表名</param>
    /// <param name="colNames">字段名</param>
    /// <param name="colTypes">字段名類型</param>
    public SQLiteDataReader CreateTable(string tableName, string[] colNames, string[] colTypes)
    {
      string queryString = "CREATE TABLE IF NOT EXISTS " + tableName + "( " + colNames[0] + " " + colTypes[0];
      for (int i = 1; i < colNames.Length; i++)
      {
        queryString += ", " + colNames[i] + " " + colTypes[i];
      }
      queryString += " ) ";
      return ExecuteQuery(queryString);
    }

    /// <summary>
    /// Reads the table.
    /// </summary>
    /// <returns>The table.</returns>
    /// <param name="tableName">Table name.</param>
    /// <param name="items">Items.</param>
    /// <param name="colNames">Col names.</param>
    /// <param name="operations">Operations.</param>
    /// <param name="colValues">Col values.</param>
    public SQLiteDataReader ReadTable(string tableName, string[] items, string[] colNames, string[] operations, string[] colValues)
    {
      string queryString = "SELECT " + items[0];
      for (int i = 1; i < items.Length; i++)
      {
        queryString += ", " + items[i];
      }
      queryString += " FROM " + tableName + " WHERE " + colNames[0] + " " + operations[0] + " " + colValues[0];
      for (int i = 0; i < colNames.Length; i++)
      {
        queryString += " AND " + colNames[i] + " " + operations[i] + " " + colValues[0] + " ";
      }
      return ExecuteQuery(queryString);
    }

    /// <summary>
    /// 本類log
    /// </summary>
    /// <param name="s"></param>
    static void Log(string s)
    {
      Console.WriteLine("class SqLiteHelper:::" + s);
    }
  }

Tips:1.別忘了引入：using System.Data.SQLite;

2.引入System.Data.SQLite.dll的同時(shí)，需要將 System.Data.SQLite.dll.config 文件放在同級(jí)目錄下。否則加載dll文件時(shí)報(bào)錯(cuò)。

2.在工程主函數(shù)Main里面添加測(cè)試代碼

class Program
  {
    private static SqLiteHelper sql;
    static void Main(string[] args)
    {
      sql = new SqLiteHelper("data source=mydb.db");
      
      
      //創(chuàng)建名為table1的數(shù)據(jù)表
      sql.CreateTable("table1", new string[] { "ID", "Name", "Age", "Email" }, new string[] { "INTEGER", "TEXT", "INTEGER", "TEXT" });
      //插入兩條數(shù)據(jù)
      sql.InsertValues("table1",new string[]{"1","張三","22","Zhang@163.com" });
      sql.InsertValues("table1", new string[] { "2", "李四", "25", "Li4@163.com" });

      //更新數(shù)據(jù)，將Name="張三"的記錄中的Name改為"Zhang3"
      sql.UpdateValues("table1", new string[] { "Name" }, new string[] { "ZhangSan" }, "Name", "Zhang3");

      //刪除Name="張三"且Age=26的記錄,DeleteValuesOR方法類似
      sql.DeleteValuesAND("table1", new string[] { "Name", "Age" }, new string[] { "張三", "22" }, new string[] { "=", "=" });


      //讀取整張表
      SQLiteDataReader reader = sql.ReadFullTable("table1");
      while (reader.Read())
      {
        //讀取ID
        Log(""+reader.GetInt32(reader.GetOrdinal("ID")));
        //讀取Name
        Log(""+reader.GetString(reader.GetOrdinal("Name")));
        //讀取Age
        Log(""+reader.GetInt32(reader.GetOrdinal("Age")));
        //讀取Email
        Log(reader.GetString(reader.GetOrdinal("Email")));
      }

      while (true)
      {
        Console.ReadLine();
      }
    }

    static void Log(string s)
    {
      Console.WriteLine(""+s);
    }
  }

Tips:1.別忘了引入：using System.Data.SQLite;

vs2015有NuGet，vs2013默認(rèn)沒(méi)有這個(gè)插件。

System.Data.SQLite 可以在VS中直接通過(guò)NuGet獲取到。

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