SQLite Helper

SQLite Helper

using System;
using System.Data;
using System.Text.RegularExpressions;
using System.Xml;
using System.IO;
using System.Collections;
using System.Data.SQLite;
using System.Configuration;//添加.net引用
namespace Tools.Common
{
    /// <summary>
    /// 对SQLite操作的类
    /// 引用：System.Data.SQLite.dll【版本：3.6.23.1（原始文件名：SQlite3.DLL）】
    /// </summary>
    public class SQLiteHelper
    {
        /// <summary>
        /// 所有成员函数都是静态的，构造函数定义为私有
        /// </summary>
        private SQLiteHelper()
        {
        }
        /// <summary>
        /// 连接字符串
        /// </summary>
        public static string ConnectionString
        {//"Data Source=Test.db3;Pooling=true;FailIfMissing=false";
            get
            {
                ////(AppSettings节点下的"SQLiteConnectionString")
                string text = ConfigurationManager.AppSettings["SQLiteConnectionString"];
                string str2 = ConfigurationManager.AppSettings["IsEncrypt"];
                if (str2 == "true")
                {
                    text = DesEncrypt.Decrypt(text);
                }
                return text;
            }
        }
        private static SQLiteConnection _Conn = null;
        /// <summary>
        /// 连接对象
        /// </summary>
        public static SQLiteConnection Conn
        {
            get
            {
                if (_Conn == null) _Conn = new SQLiteConnection(ConnectionString);
                return SQLiteHelper._Conn;
            }
            set { SQLiteHelper._Conn = value; }
        }
        

        #region CreateCommand(commandText,SQLiteParameter[])
        /// <summary>
        /// 创建命令
        /// </summary>
        /// <param name="connection">连接</param>
        /// <param name="commandText">语句</param>
        /// <param name="commandParameters">语句参数.</param>
        /// <returns>SQLite Command</returns>
        public static SQLiteCommand CreateCommand(string commandText, params SQLiteParameter[] commandParameters)
        {
            SQLiteCommand cmd = new SQLiteCommand(commandText, Conn);
            if (commandParameters.Length > 0)
            {
                foreach (SQLiteParameter parm in commandParameters)
                    cmd.Parameters.Add(parm);
            }
            return cmd;
        }
        #endregion


        #region CreateParameter(parameterName,parameterType,parameterValue)
        /// <summary>
        /// 创建参数
        /// </summary>
        /// <param name="parameterName">参数名</param>
        /// <param name="parameterType">参数类型</param>
        /// <param name="parameterValue">参数值</param>
        /// <returns>返回创建的参数</returns>
        public static SQLiteParameter CreateParameter(string parameterName, System.Data.DbType parameterType, object parameterValue)
        {
            SQLiteParameter parameter = new SQLiteParameter();
            parameter.DbType = parameterType;
            parameter.ParameterName = parameterName;
            parameter.Value = parameterValue;
            return parameter;
        }
        #endregion

        #region ExecuteDataSet(commandText,paramList[])
        /// <summary>
        /// 查询数据集
        /// </summary>
        /// <param name="cn">连接.</param>
        /// <param name="commandText">查询语句.</param>
        /// <param name="paramList">object参数列表.</param>
        /// <returns></returns>
        public static DataSet ExecuteDataSet( string commandText,params object[] paramList)
        {

            SQLiteCommand cmd = Conn.CreateCommand();
            cmd.CommandText = commandText;
            if (paramList != null)
            {
                AttachParameters(cmd, commandText, paramList);
            }
            DataSet ds = new DataSet();
            if (Conn.State == ConnectionState.Closed)
                Conn.Open();
            SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);
            da.Fill(ds);
            da.Dispose();
            cmd.Dispose();
            Conn.Close();
            return ds;
        } 
        #endregion

        #region ExecuteDataSet(SQLiteCommand)
        /// <summary>
        /// 查询数据集
        /// </summary>
        /// <param name="cmd">SQLiteCommand对象</param>
        /// <returns>返回数据集</returns>
        public static DataSet ExecuteDataSet(SQLiteCommand cmd)
        {
            if (cmd.Connection.State == ConnectionState.Closed)
                cmd.Connection.Open();
            DataSet ds = new DataSet();
            SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);
            da.Fill(ds);
            da.Dispose();
            cmd.Connection.Close();
            cmd.Dispose();
            return ds;
        } 
        #endregion

        #region ExecuteDataSet(SQLiteTransaction,commandText,params SQLiteParameter[])
        /// <summary>
        /// 查询数据集
        /// </summary>
        /// <param name="transaction">SQLiteTransaction对象. </param>
        /// <param name="commandText">查询语句.</param>
        /// <param name="commandParameters">命令的参数列表.</param>
        /// <returns>DataSet</returns>
        /// <remarks>必须手动执行关闭连接transaction.connection.Close</remarks>
        public static DataSet ExecuteDataSet(SQLiteTransaction transaction, string commandText, params SQLiteParameter[] commandParameters)
        {
            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed, please provide an open transaction.", "transaction");
            IDbCommand cmd = transaction.Connection.CreateCommand();
            cmd.CommandText = commandText;
            foreach (SQLiteParameter parm in commandParameters)
            {
                cmd.Parameters.Add(parm);
            }
            if (transaction.Connection.State == ConnectionState.Closed)
                transaction.Connection.Open();
            DataSet ds = ExecuteDataSet((SQLiteCommand)cmd);
            return ds;
        } 
        #endregion

        #region ExecuteDataSet(SQLiteTransaction,commandText,object[] commandParameters)
        /// <summary>
        /// 查询数据集
        /// </summary>
        /// <param name="transaction">SQLiteTransaction对象 </param>
        /// <param name="commandText">查询语句.</param>
        /// <param name="commandParameters">命令参数列表</param>
        /// <returns>返回数据集</returns>
        /// <remarks>必须手动执行关闭连接transaction.connection.Close</remarks>
        public static DataSet ExecuteDataSet(SQLiteTransaction transaction, string commandText, object[] commandParameters)
        {

            if (transaction == null) throw new ArgumentNullException("transaction");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed,                                                          please provide an open transaction.", "transaction");
            IDbCommand cmd = transaction.Connection.CreateCommand();
            cmd.CommandText = commandText;
            AttachParameters((SQLiteCommand)cmd, cmd.CommandText, commandParameters);
            if (transaction.Connection.State == ConnectionState.Closed)
                transaction.Connection.Open();

            DataSet ds = ExecuteDataSet((SQLiteCommand)cmd);
            return ds;
        } 
        #endregion

        #region UpdateDataset(insertCommand,deleteCommand,updateCommand,dataSet,tableName)
        /// <summary>
        /// 更新数据集中数据到数据库
        /// </summary>
        /// <param name="insertCommand">insert语句</param>
        /// <param name="deleteCommand">delete语句</param>
        /// <param name="updateCommand">update语句</param>
        /// <param name="dataSet">要更新的DataSet</param>
        /// <param name="tableName">数据集中要更新的table名</param>
        public static void UpdateDataset(SQLiteCommand insertCommand, SQLiteCommand deleteCommand, SQLiteCommand updateCommand, DataSet dataSet, string tableName)
        {
            if (insertCommand == null) throw new ArgumentNullException("insertCommand");
            if (deleteCommand == null) throw new ArgumentNullException("deleteCommand");
            if (updateCommand == null) throw new ArgumentNullException("updateCommand");
            if (tableName == null || tableName.Length == 0) throw new ArgumentNullException("tableName");

            // Create a SQLiteDataAdapter, and dispose of it after we are done
            using (SQLiteDataAdapter dataAdapter = new SQLiteDataAdapter())
            {
                // Set the data adapter commands

                dataAdapter.UpdateCommand = updateCommand;
                dataAdapter.InsertCommand = insertCommand;
                dataAdapter.DeleteCommand = deleteCommand;
                // Update the dataset changes in the data source
                dataAdapter.Update(dataSet, tableName);

                // Commit all the changes made to the DataSet
                dataSet.AcceptChanges();
            }
        }
        #endregion

        #region ExecuteReader(SQLiteCommand,commandText, object[] paramList)
        /// <summary>
        /// ExecuteReader方法
        /// </summary>
        /// <param name="cmd">查询命令</param>
        /// <param name="commandText">含有类似@colume参数的sql语句</param>
        /// <param name="paramList">语句参数列表</param>
        /// <returns>IDataReader</returns>
        public static IDataReader ExecuteReader(SQLiteCommand cmd, string commandText, object[] paramList)
        {
            if (cmd.Connection == null)
                throw new ArgumentException("没有为命令指定活动的连接.", "cmd");
            cmd.CommandText = commandText;
            AttachParameters(cmd, commandText, paramList);
            if (cmd.Connection.State == ConnectionState.Closed)
                cmd.Connection.Open();
            IDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            return rdr;
        } 
        #endregion

        #region ExecuteNonQuery(commandText,paramList)
        /// <summary>
        /// 执行ExecuteNonQuery方法
        /// </summary>
        /// <param name="cn">连接</param>
        /// <param name="commandText">语句</param>
        /// <param name="paramList">参数</param>
        /// <returns></returns>
        public static int ExecuteNonQuery(string commandText, params  object[] paramList)
        {

            SQLiteCommand cmd = Conn.CreateCommand();
            cmd.CommandText = commandText;
            AttachParameters(cmd, commandText, paramList);
            if (Conn.State == ConnectionState.Closed)
                Conn.Open();
            int result = cmd.ExecuteNonQuery();
            cmd.Dispose();
            Conn.Close();

            return result;
        } 
        #endregion

        #region ExecuteNonQuery(SQLiteTransaction,commandText,paramList)
        /// <summary>
        /// 执行ExecuteNonQuery方法,带事务
        /// </summary>
        /// <param name="transaction">之前创建好的SQLiteTransaction对象</param>
        /// <param name="commandText">语句.</param>
        /// <param name="paramList">参数.</param>
        /// <returns>返回影响的行数</returns>
        /// <remarks>
        /// 定义事务  DbTransaction trans = conn.BeginTransaction();
        ///     或者：SQLiteTransaction trans = Conn.BeginTransaction();
        /// 操作代码示例：
        /// try
        ///{
        ///    // 连续操作记录 
        ///    for (int i = 0; i < 1000; i++)
        ///    {
        ///        ExecuteNonQuery(trans,commandText,[] paramList);
        ///    }
        ///    trans.Commit();
        ///}
        ///catch
        ///{
        ///    trans.Rollback();
        ///    throw;
        ///}
        ///trans.Connection.Close();//关闭事务连接
        ///transaction.Dispose();//释放事务对象
        /// </remarks>
        public static int ExecuteNonQuery(SQLiteTransaction transaction, string commandText, params  object[] paramList)
        {
            if (transaction == null) throw new ArgumentNullException("transaction is null");
            if (transaction != null && transaction.Connection == null) throw new ArgumentException("The transaction was rolled back or committed,please provide an open transaction.", "transaction");
            using (IDbCommand cmd = transaction.Connection.CreateCommand())
            {
                cmd.CommandText = commandText;
                AttachParameters((SQLiteCommand)cmd, cmd.CommandText, paramList);
                if (transaction.Connection.State == ConnectionState.Closed)
                    transaction.Connection.Open();
                int result = cmd.ExecuteNonQuery(); 
                return result;
            }
            
        } 
        #endregion

        #region ExecuteNonQuery(IDbCommand)
        /// <summary>
        /// 执行ExecuteNonQuery方法
        /// </summary>
        /// <param name="cmd">创建好的命令.</param>
        /// <returns></returns>
        public static int ExecuteNonQuery(IDbCommand cmd)
        {
            if (cmd.Connection.State == ConnectionState.Closed)
                cmd.Connection.Open();
            int result = cmd.ExecuteNonQuery();
            cmd.Connection.Close();
            cmd.Dispose();
            return result;
        } 
        #endregion

        #region ExecuteScalar(commandText,paramList)
        /// <summary>
        /// 执行ExecuteScalar
        /// </summary>
        /// <param name="commandText">语句s</param>
        /// <param name="paramList">参数</param>
        /// <returns></returns>
        public static object ExecuteScalar(string commandText, params  object[] paramList)
        {
            SQLiteConnection cn = new SQLiteConnection(ConnectionString);
            SQLiteCommand cmd = cn.CreateCommand();
            cmd.CommandText = commandText;
            AttachParameters(cmd, commandText, paramList);
            if (cn.State == ConnectionState.Closed)
                cn.Open();
            object result = cmd.ExecuteScalar();
            cmd.Dispose();
            cn.Close();
            return result;
        } 
        #endregion

        #region ExecuteXmlReader(IDbCommand)
        /// <summary>
        /// ExecuteXmlReader返回xml格式
        /// </summary>
        /// <param name="command">语句</param>
        /// <returns>返回XmlTextReader对象</returns>
        public static XmlReader ExecuteXmlReader(IDbCommand command)
        { // open the connection if necessary, but make sure we 
            // know to close it when we�re done.
            if (command.Connection.State != ConnectionState.Open)
            {
                command.Connection.Open();
            }

            // get a data adapter  
            SQLiteDataAdapter da = new SQLiteDataAdapter((SQLiteCommand)command);
            DataSet ds = new DataSet();
            // fill the data set, and return the schema information
            da.MissingSchemaAction = MissingSchemaAction.AddWithKey;
            da.Fill(ds);
            // convert our dataset to XML
            StringReader stream = new StringReader(ds.GetXml());
            command.Connection.Close();
            // convert our stream of text to an XmlReader
            return new XmlTextReader(stream);
        } 
        #endregion

        #region AttachParameters(SQLiteCommand,commandText,object[] paramList)
        /// <summary>
        /// 增加参数到命令（自动判断类型）
        /// </summary>
        /// <param name="commandText">命令语句</param>
        /// <param name="paramList">object参数列表</param>
        /// <returns>返回SQLiteParameterCollection参数列表</returns>
        /// <remarks>Status experimental. Regex appears to be handling most issues. Note that parameter object array must be in same ///order as parameter names appear in SQL statement.</remarks>
        private static SQLiteParameterCollection AttachParameters(SQLiteCommand cmd, string commandText, params  object[] paramList)
        {
            if (paramList == null || paramList.Length == 0) return null;

            SQLiteParameterCollection coll = cmd.Parameters;
            string parmString = commandText.Substring(commandText.IndexOf("@"));
            // pre-process the string so always at least 1 space after a comma.
            parmString = parmString.Replace(",", " ,");
            // get the named parameters into a match collection
            string pattern = @"(@)S*(.*?)";
            Regex ex = new Regex(pattern, RegexOptions.IgnoreCase);
            MatchCollection mc = ex.Matches(parmString);
            string[] paramNames = new string[mc.Count];
            int i = 0;
            foreach (Match m in mc)
            {
                paramNames[i] = m.Value;
                i++;
            }

            // now let's type the parameters
            int j = 0;
            Type t = null;
            foreach (object o in paramList)
            {
                t = o.GetType();

                SQLiteParameter parm = new SQLiteParameter();
                switch (t.ToString())
                {

                    case ("DBNull"):
                    case ("Char"):
                    case ("SByte"):
                    case ("UInt16"):
                    case ("UInt32"):
                    case ("UInt64"):
                        throw new SystemException("Invalid data type");


                    case ("System.String"):
                        parm.DbType = DbType.String;
                        parm.ParameterName = paramNames[j];
                        parm.Value = (string)paramList[j];
                        coll.Add(parm);
                        break;

                    case ("System.Byte[]"):
                        parm.DbType = DbType.Binary;
                        parm.ParameterName = paramNames[j];
                        parm.Value = (byte[])paramList[j];
                        coll.Add(parm);
                        break;

                    case ("System.Int32"):
                        parm.DbType = DbType.Int32;
                        parm.ParameterName = paramNames[j];
                        parm.Value = (int)paramList[j];
                        coll.Add(parm);
                        break;

                    case ("System.Boolean"):
                        parm.DbType = DbType.Boolean;
                        parm.ParameterName = paramNames[j];
                        parm.Value = (bool)paramList[j];
                        coll.Add(parm);
                        break;

                    case ("System.DateTime"):
                        parm.DbType = DbType.DateTime;
                        parm.ParameterName = paramNames[j];
                        parm.Value = Convert.ToDateTime(paramList[j]);
                        coll.Add(parm);
                        break;

                    case ("System.Double"):
                        parm.DbType = DbType.Double;
                        parm.ParameterName = paramNames[j];
                        parm.Value = Convert.ToDouble(paramList[j]);
                        coll.Add(parm);
                        break;

                    case ("System.Decimal"):
                        parm.DbType = DbType.Decimal;
                        parm.ParameterName = paramNames[j];
                        parm.Value = Convert.ToDecimal(paramList[j]);
                        break;

                    case ("System.Guid"):
                        parm.DbType = DbType.Guid;
                        parm.ParameterName = paramNames[j];
                        parm.Value = (System.Guid)(paramList[j]);
                        break;

                    case ("System.Object"):

                        parm.DbType = DbType.Object;
                        parm.ParameterName = paramNames[j];
                        parm.Value = paramList[j];
                        coll.Add(parm);
                        break;

                    default:
                        throw new SystemException("Value is of unknown data type");

                } // end switch

                j++;
            }
            return coll;
        } 
        #endregion

        #region ExecuteNonQueryTypedParams(IDbCommand, DataRow)
        /// <summary>
        /// Executes non query typed params from a DataRow
        /// </summary>
        /// <param name="command">Command.</param>
        /// <param name="dataRow">Data row.</param>
        /// <returns>Integer result code</returns>
        public static int ExecuteNonQueryTypedParams(IDbCommand command, DataRow dataRow)
        {
            int retVal = 0;

            // If the row has values, the store procedure parameters must be initialized
            if (dataRow != null && dataRow.ItemArray.Length > 0)
            {
                // Set the parameters values
                AssignParameterValues(command.Parameters, dataRow);

                retVal = ExecuteNonQuery(command);
            }
            else
            {
                retVal = ExecuteNonQuery(command);
            }

            return retVal;
        } 
        #endregion

        #region AssignParameterValues
        /// <summary>
        /// This method assigns dataRow column values to an IDataParameterCollection
        /// </summary>
        /// <param name="commandParameters">The IDataParameterCollection to be assigned values</param>
        /// <param name="dataRow">The dataRow used to hold the command's parameter values</param>
        /// <exception cref="System.InvalidOperationException">Thrown if any of the parameter names are invalid.</exception>
        protected internal static void AssignParameterValues(IDataParameterCollection commandParameters, DataRow dataRow)
        {
            if (commandParameters == null || dataRow == null)
            {
                // Do nothing if we get no data
                return;
            }

            DataColumnCollection columns = dataRow.Table.Columns;

            int i = 0;
            // Set the parameters values
            foreach (IDataParameter commandParameter in commandParameters)
            {
                // Check the parameter name
                if (commandParameter.ParameterName == null ||
                 commandParameter.ParameterName.Length <= 1)
                    throw new InvalidOperationException(string.Format(
                           "Please provide a valid parameter name on the parameter #{0},                            the ParameterName property has the following value: '{1}'.",
                     i, commandParameter.ParameterName));

                if (columns.Contains(commandParameter.ParameterName))
                    commandParameter.Value = dataRow[commandParameter.ParameterName];
                else if (columns.Contains(commandParameter.ParameterName.Substring(1)))
                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];

                i++;
            }
        } 
        #endregion

        #region AssignParameterValues
        /// <summary>
        /// This method assigns dataRow column values to an array of IDataParameters
        /// </summary>
        /// <param name="commandParameters">Array of IDataParameters to be assigned values</param>
        /// <param name="dataRow">The dataRow used to hold the stored procedure's parameter values</param>
        /// <exception cref="System.InvalidOperationException">Thrown if any of the parameter names are invalid.</exception>
        protected void AssignParameterValues(IDataParameter[] commandParameters, DataRow dataRow)
        {
            if ((commandParameters == null) || (dataRow == null))
            {
                // Do nothing if we get no data
                return;
            }

            DataColumnCollection columns = dataRow.Table.Columns;

            int i = 0;
            // Set the parameters values
            foreach (IDataParameter commandParameter in commandParameters)
            {
                // Check the parameter name
                if (commandParameter.ParameterName == null ||
                 commandParameter.ParameterName.Length <= 1)
                    throw new InvalidOperationException(string.Format(
                     "Please provide a valid parameter name on the parameter #{0}, the ParameterName property has the following value: '{1}'.",
                     i, commandParameter.ParameterName));

                if (columns.Contains(commandParameter.ParameterName))
                    commandParameter.Value = dataRow[commandParameter.ParameterName];
                else if (columns.Contains(commandParameter.ParameterName.Substring(1)))
                    commandParameter.Value = dataRow[commandParameter.ParameterName.Substring(1)];

                i++;
            }
        } 
        #endregion

        #region AssignParameterValues
        /// <summary>
        /// This method assigns an array of values to an array of IDataParameters
        /// </summary>
        /// <param name="commandParameters">Array of IDataParameters to be assigned values</param>
        /// <param name="parameterValues">Array of objects holding the values to be assigned</param>
        /// <exception cref="System.ArgumentException">Thrown if an incorrect number of parameters are passed.</exception>
        protected void AssignParameterValues(IDataParameter[] commandParameters, params  object[] parameterValues)
        {
            if ((commandParameters == null) || (parameterValues == null))
            {
                // Do nothing if we get no data
                return;
            }

            // We must have the same number of values as we pave parameters to put them in
            if (commandParameters.Length != parameterValues.Length)
            {
                throw new ArgumentException("Parameter count does not match Parameter Value count.");
            }

            // Iterate through the IDataParameters, assigning the values from the corresponding position in the 
            // value array
            for (int i = 0, j = commandParameters.Length, k = 0; i < j; i++)
            {
                if (commandParameters[i].Direction != ParameterDirection.ReturnValue)
                {
                    // If the current array value derives from IDataParameter, then assign its Value property
                    if (parameterValues[k] is IDataParameter)
                    {
                        IDataParameter paramInstance;
                        paramInstance = (IDataParameter)parameterValues[k];
                        if (paramInstance.Direction == ParameterDirection.ReturnValue)
                        {
                            paramInstance = (IDataParameter)parameterValues[++k];
                        }
                        if (paramInstance.Value == null)
                        {
                            commandParameters[i].Value = DBNull.Value;
                        }
                        else
                        {
                            commandParameters[i].Value = paramInstance.Value;
                        }
                    }
                    else if (parameterValues[k] == null)
                    {
                        commandParameters[i].Value = DBNull.Value;
                    }
                    else
                    {
                        commandParameters[i].Value = parameterValues[k];
                    }
                    k++;
                }
            }
        } 
        #endregion


    }
}

使用：

<appSettings>
<add key="SQLiteConnectionString" value="Data Source=Test.db3;Pooling=true;FailIfMissing=false"/>
</appSettings>

其他参考：

https://sh.codeplex.com/

Change Log

27 March 2014 - V1.2

• Added parameter support for "Select", "Execute" and "ExecuteScalar" methods.

22 March 2014 - V1.1

• Add: Parameterized SQL Execution Support
• New Method: Update Table's Structure
• New Method: LastInsertRowId
• New Method: GetTableList
• New Method: ShowDatabase
• New Method: AttachDatabase, DetachDatabase
• Modify: ExecuteScalar applies generics.
• Demo App Updated

List of Simplified Functions

1. GetTableStatus
2. GetTableList
3. GetColumnStatus
4. CreateTable
5. UpdateTableStructure
6. BeginTransaction, Commit, Rollback
7. Select
8. Execute
9. ExecuteScalar
10. Escape
11. Insert
12. Update
13. LastInsertRowId
14. RenameTable
15. CopyAllData
16. DropTable
17. ShowDatabase
18. AttachDatabase, DetachDatabase

Getting Start

Add this using statement at the top of your class:

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using System.Data.SQLite;

SQLiteConnection and SQLiteCommand have to be initialized before using SQLiteHelper:

Example:

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using (SQLiteConnection conn = new SQLiteConnection("data source=C:\data"))
{
    using (SQLiteCommand cmd = new SQLiteCommand())
    {
        cmd.Connection = conn;
        conn.Open();
 
        SQLiteHelper sh = new SQLiteHelper(cmd);
 
        // do something...

        conn.Close();
    }
}

1. GetTableStatus

Get all information of tables in the database.

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DataTable dt = sh.GetTableStatus();

Sample result:

type	name	tbl_name	rootpage	sql
table	sqlite_sequence	sqlite_sequence	3	CREATE TABLE sqlite_sequence(name,seq)
table	person2	person2	5	CREATE TABLE "person2"( id integer primary key autoincrement, name text, tel text, email text, job text, remarks text)
table	player	player	4	CREATE TABLE `player`( id integer primary key autoincrement, lvl integer, weaponid integer, teamid integer, location text, team_name text, remarks text)
table	product	product	6	CREATE TABLE "product"( id integer primary key autoincrement, name text, qty integer)

2. GetTableList

Get a list of tables in database.

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DataTable dt = sh.GetTableList();

3. GetColumnStatus

Get all information of columns in specific table.

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// Get column's information from table "person"
DataTable dt = sh.GetColumnStatus("person");

Sample Result:

cid	name	type	notnull	dflt_value	pk
0	id	integer	0		1
1	lvl	integer	0		0
2	weaponid	integer	0		0
3	teamid	integer	0		0
4	location	text	0		0
5	team_name	text	0		0
6	remarks	text	0		0

4. CreateTable

Create table.

Example table structure: Person

Column Name	Data Type	Primary Key	Auto Increment	Not Null	Default Value
id	int	true	true
name	text
membershipid	int
level	decimal				5.5

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SQLiteTable tb = new SQLiteTable("person");
 
tb.Columns.Add(new SQLiteColumn("id", true));
tb.Columns.Add(new SQLiteColumn("name"));
tb.Columns.Add(new SQLiteColumn("membershipid", ColType.Integer));
tb.Columns.Add(new SQLiteColumn("level", ColType.Decimal, false, false, "5.5"));
 
sh.CreateTable(tb);

5. UpdateTableStructure

As the name said, it is used to update a table's structure. Maybe you have added new columns, or drop/deleted some columns. This method helps you to update it.

The process at code behind:

• Assume that the old table is named: person
• The class creates a temporary table (named: person_temp) with your new defined structure.
• Copy all rows from person to person_temp.
• Drop/delete table of person.
• Rename table of person_temp to person

Code example:

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SQLiteTable tb = new SQLiteTable();
tb.Columns.Add(new SQLiteColumn("id", true));
tb.Columns.Add(new SQLiteColumn("name"));
tb.Columns.Add(new SQLiteColumn("sku"));
tb.Columns.Add(new SQLiteColumn("code"));
tb.Columns.Add(new SQLiteColumn("category"));
tb.Columns.Add(new SQLiteColumn("remarks"));

sh.UpdateTableStructure("person", tb);

6. BeginTransaction, Commit, Rollback

What is transaction?

By default, every SQL query that is sent to SQLite database engine happens in a transaction. The engine automatically BEGIN a transaction and COMMIT it at the end. COMMIT is something like "Make it take effect".

If we send 3 SQL queries (INSERT, UPDATE, DELETE, etc...), 3 transactions are taken place. According to [SQLite official documentation - Frequently Asked Questions]:

"...A transaction normally requires two complete rotations of the disk platter, which on a 7200RPM disk drive limits you to about 60 transactions per second..."

Which means, with a 7200RPM hard disk, the best that we can do is 60 INSERTs (or UPDATE, DELETE, etc) per second.

But, If we manually issue a BEGIN TRANSACTION, all the queries will be wrapped in single transaction, then SQLite can execute huge amount of queries per second. Somebody said he can execute 10 million per second at [stackoverflow.com], but this is also depends on the speed of hard disk that you are using.

Code example with SQLiteHelper:

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sh.BeginTransaction();
 
try
{
    // INSERT.....
    // INSERT.....
    // UPDATE....
    // ... skip for another 50,000 queries....
    // DELETE....
    // UPDATE...
    // INSERT.....

    sh.Commit();
}
catch
{
    sh.Rollback();
}

ROLLBACK, in the above example means Cancel Transaction. All queries that have sent to SQLite database within that specific transaction are dismissed.

7. Select

Return the query result in DataTable format.

• Select(string sql)
• Select(string sql, Dictionary<string, object> dicParameters = null)
• Select(string sql, IEnumerable<SQLiteParameter> parameters = null)

Example 1:

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DataTable dt = sh.Select("select * from person order by id;");

Example 2 (With parameters support):

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var dic = new Dictionarystring, object();
dic["@aaa"] = 1;
dic["@bbb"] = 1;
DataTable dt = sh.Select("select * from member where membershipid = @aaa and locationid = @bbb;", dic);

Example 3 (With parameters support):

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DataTable dt = sh.Select("select * from member where membershipid = @aaa and locationid = @bbb;",
    new SQLiteParameter[] { 
        new SQLiteParameter("@aaa", 1),
        new SQLiteParameter("@bbb", 1)
    });

8. Execute

Execute single SQL query.

• Execute(string sql)
• Execute(string sql, Dictionary<string, object> dicParameters = null)
• Execute(string sql, IEnumerable<SQLiteParameter> parameters = null)

Example:

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sh.Execute("insert into person(name)values('hello');");

9. ExecuteScalar

Return the result of first row first column in specific data type.

• ExecuteScalar(string sql)
• ExecuteScalar(string sql, Dictionary<string, object> dicParameters = null)
• ExecuteScalar(string sql, IEnumerable<SQLiteParameter> parameters = null)
• ExecuteScalar<datatype>(string sql)
• ExecuteScalar<datatype>(string sql, Dictionary<string, object> dicParameters = null)
• ExecuteScalar<datatype>(string sql, IEnumerable<SQLiteParameter> parameters = null)

Example:

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string a = sh.ExecuteScalar<string>("select 'Hello!';");

int b = sh.ExecuteScalar<int>("select 1000;");

decimal c = sh.ExecuteScalar<decimal>("select 4.4;");

DateTime d = sh.ExecuteScalar<DateTime>("select date('now');");

byte[] e = sh.ExecuteScalar<byte[]>("select randomblob(16);");

10. Escape

Escape string sequence for text value to avoid SQL injection or invalid SQL syntax to be constructed.

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sh.Execute("insert into person(name) values('" + Escape(input) + "');");

11. Insert

Insert new row of data. All data will be added as parameters at code behind. This support blob (byte[]) value too.

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var dic = new Dictionary<string, object>();
dic["name"] = "John";
dic["membershipid"] = 1;
dic["level"] = 6.8;
 
sh.Insert("person", dic);

12. Update

Update row. All data will be added as parameters at code behind. This support blob (byte[]) value too.

Example 1: Update with single condition (where id = 1)

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var dicData = new Dictionary<string, object>();
dicData["name"] = "no name";
dicData["membershipid"] = 0;
dicData["level"] = 5.5;
 
sh.Update("person", dicData, "id", 1);

Example 2: Update with multiple condition (where membership = 1 and level = 5.5 and teamid = 1)

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var dicData = new Dictionary<string, object>();
dicData["name"] = "no name";
dicData["status"] = 0;
dicData["money"] = 100;
dicData["dateregister"] = DateTime.MinValue;
 
var dicCondition = new Dictionary<string, object>();
dicCondition["membershipid"] = 1;
dicCondition["level"] = 5.5;
dicCondition["teamid"] = 1;
 
sh.Update("person", dicData, dicCondition);

13. LastInsertRowId

Get the last issued id (Auto-Increment)

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sh.Insert("person", dicData);
long id = sh.LastInsertRowId();

14. RenameTable

Rename a table.

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sh.RenameTable("person", "person_backup");

15. CopyAllData

Copy all data from one table to another.

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sh.CopyAllData("person", "person_new");

Before copying, SQLiteHelper will scan the two tables for match columns. Only columns that exist in both tables will be copied.

16. DropTable

Drop table, delete a table

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sh.DropTable("person");

17. ShowDatabase

Display attached databases.

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DataTable dt = sh.ShowDatabase();

18. AttachDatabase, DetachDatabase

Attach or detach a database

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sh.AttachDatabase("C:\data2013.sq3", "lastyeardb");
sb.DetachDatabase("lastyeardb");

That's it, guys/girls. Comments are welcome.