SQLite之C#版 System.Data.SQLite使用方法
SQLite簡介
SQLite,是一款輕型的關系型數(shù)據(jù)庫。它的設計目標是嵌入式。
它能夠支持Windows/Linux/Unix等等主流的操作系統(tǒng),同時能夠跟很多程序語言相結合,比如 C++、C#、Object-C、PHP、Java等。
我是做手游開發(fā)的,在手機上使用SQLite 存儲數(shù)據(jù)是很方便的。
System.Data.SqLite實踐前期準備
- System.Data.SQLite 庫下載,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版本下載相應的的System.Data.SQLite。 下載解壓文件如:

安裝在指定目錄后生成多個dll文件:

本文測試用的只有 System.Data.SQLite.dll 。對于SQLite庫數(shù)據(jù)的增刪改查已經(jīng)足夠用了。
2.SQLite數(shù)據(jù)庫文件以.db為后綴。安裝SQLite可視化工具后如圖:

mydb是我測試用的數(shù)據(jù)庫。
實踐
對SQLite的增、刪、改、查。
測試環(huán)境:VS2015 語言:C#
創(chuàng)建控制臺新工程,引入System.Data.SQLite.dll 文件。
1.編寫SQLite 操作類, 對SQLite數(shù)據(jù)操作進行封裝為 SqLiteHelper,代碼如下:
/// <summary>
/// SQLite 操作類
/// </summary>
class SqLiteHelper
{
/// <summary>
/// 數(shù)據(jù)庫連接定義
/// </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>
/// 構造函數(shù)
/// </summary>
/// <param name="connectionString">連接SQLite庫字符串</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>
/// 關閉數(shù)據(jù)庫連接
/// </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;
//當插入的數(shù)據(jù)長度不等于字段數(shù)目時引發(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">字段名對應的數(shù)據(jù)</param>
/// <param name="key">關鍵字</param>
/// <param name="value">關鍵字對應的值</param>
/// <param name="operation">運算符:=,<,>,...,默認“=”</param>
public SQLiteDataReader UpdateValues(string tableName, string[] colNames, string[] colValues, string key, string value, string operation="=")
{
//當字段名稱和字段數(shù)值不對應時引發(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">字段名對應的數(shù)據(jù)</param>
public SQLiteDataReader DeleteValuesOR(string tableName, string[] colNames, string[] colValues, string[] operations)
{
//當字段名稱和字段數(shù)值不對應時引發(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">字段名對應的數(shù)據(jù)</param>
public SQLiteDataReader DeleteValuesAND(string tableName, string[] colNames, string[] colValues, string[] operations)
{
//當字段名稱和字段數(shù)值不對應時引發(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,需要將 System.Data.SQLite.dll.config 文件放在同級目錄下。否則加載dll文件時報錯。
2.在工程主函數(shù)Main里面添加測試代碼
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默認沒有這個插件。
System.Data.SQLite 可以在VS中直接通過NuGet獲取到。
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