diff --git a/2019/03/SQLiteDatabase.cs b/2019/03/SQLiteDatabase.cs
new file mode 100644
index 0000000..a3bec00
--- /dev/null
+++ b/2019/03/SQLiteDatabase.cs
@@ -0,0 +1,469 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Data.SQLite;
+using System.IO;
+using System.Text;
+
+namespace RyzStudio.Data.SQLite
+{
+    public class SQLiteDatabase
+    {
+		public SQLiteConnection DBConnection { get; protected set; } = null;
+
+		public string DBLocation { get; protected set; } = null;
+
+		public string LastError { get; protected set; } = null;
+
+		public int LastInsertID
+		{
+			get
+			{
+				if (this.DBConnection == null)
+				{
+					return 0;
+				}
+
+				DataTable dt = this.DoQuery("SELECT last_insert_rowid() AS rv;");
+				if (dt == null)
+				{
+					return 0;
+				}
+
+				if (dt.Rows.Count <= 0)
+				{
+					return 0;
+				}
+
+				int n;
+				if (!int.TryParse(dt.Rows[0]["rv"].ToString(), out n))
+				{
+					n = 0;
+				}
+
+				return n;
+			}
+		}
+
+		protected string[] requiredTableList = new string[0];
+
+		protected const string appSettingsTableName = "ryz_app_xxxx_config";
+
+        public bool Create()
+        {
+			this.LastError = string.Empty;
+
+            this.DBLocation = ":memory:";
+
+            try
+            {
+				this.DBConnection = new SQLiteConnection(string.Concat("Data Source=\"", this.DBLocation, "\";Version=3;UTF8Encoding=True;"));
+				this.DBConnection.Open();
+            }
+            catch (Exception exc)
+            {
+				this.LastError = exc.Message;
+
+                return false;
+            }
+
+            return true;
+        }
+
+        public bool Create(string filename, bool overwriteFile = false, string password = null, bool useAppSettings = false)
+        {
+			bool rs = create(filename, overwriteFile, password);
+
+			if (useAppSettings)
+			{
+				if (!rs)
+				{
+					return false;
+				}
+
+				rs = prepareDatabase();
+				if (!rs)
+				{
+					return false;
+				}
+
+				return this.HasRequiredTables();
+			}
+			else
+			{
+				return rs;
+			}
+        }
+
+        public bool LoadFile(string filename, string password = null)
+        {
+			this.LastError = string.Empty;
+
+            if (!File.Exists(filename))
+            {
+                return false;
+            }
+
+			this.DBLocation = filename;
+
+            try
+            {
+				this.DBConnection = new SQLiteConnection(string.Concat("Data Source=\"", filename, "\";Version=3;UTF8Encoding=True;", (password == null) ? string.Empty : string.Concat("Password=", encode64(password), ";")));
+				this.DBConnection.Open();
+            }
+            catch (Exception exc)
+            {
+				this.LastError = exc.Message;
+
+                return false;
+            }
+
+            return true;
+        }
+
+        public void Close()
+        {
+			this.LastError = string.Empty;
+
+			if (this.DBConnection != null)
+            {			
+				try
+                {
+					this.DBConnection.Cancel();
+					this.DBConnection.Close();
+					this.DBConnection.Dispose();
+					this.DBConnection = null;
+
+					SQLiteConnection.ClearAllPools();
+					GC.Collect();
+				}
+				catch (Exception exc)
+				{
+					this.LastError = exc.Message;
+				}
+            }
+        }
+
+        public DataTable DoQuery(string query)
+        {
+			this.LastError = string.Empty;
+
+            if (this.DBConnection == null)
+            {
+                return null;
+            }
+
+            try
+            {
+                SQLiteCommand command = new SQLiteCommand(query, this.DBConnection);
+                SQLiteDataReader dr = command.ExecuteReader();
+
+                DataTable dt = new DataTable();
+                dt.Load(dr);
+
+                return dt;
+            }
+            catch (Exception exc)
+            {
+				this.LastError = exc.Message;
+
+                return null;
+            }
+        }
+
+        public DataTable DoQuery(string query, params string[] args) => DoQuery(prepareQuery(query, args));
+
+        public int DoQueryCount(string query)
+        {
+			this.LastError = string.Empty;
+
+            if (this.DBConnection == null)
+            {
+                return -1;
+            }
+
+            DataTable dt = this.DoQuery(query);
+            if (dt == null)
+            {
+                return -1;
+            }
+
+            return dt.Rows.Count;
+        }
+
+        public int DoQueryCount(string query, params string[] args) => this.DoQueryCount(prepareQuery(query, args));
+
+        public bool DoQueryExist(string query) => (this.DoQueryCount(query) > 0);
+
+        public bool DoQueryExist(string query, params string[] args) => this.DoQueryExist(prepareQuery(query, args));
+
+        public string DoQuerySingle(string query)
+        {
+			this.LastError = string.Empty;
+
+            if (this.DBConnection == null)
+            {
+                return string.Empty;
+            }
+
+            DataTable dt = this.DoQuery(query);
+
+            if (dt == null)
+            {
+                return string.Empty;
+            }
+
+            if (dt.Columns.Count <= 0)
+            {
+                return string.Empty;
+            }
+
+            if (dt.Rows.Count <= 0)
+            {
+                return string.Empty;
+            }
+
+            if (dt.Rows[0][0] is byte[])
+            {
+                return Encoding.UTF8.GetString(dt.Rows[0][0] as byte[]);
+            }
+            else
+            {
+                return dt.Rows[0][0].ToString();
+            }          
+        }
+
+        public string DoQuerySingle(string query, params string[] args) => this.DoQuerySingle(prepareQuery(query, args));
+
+        public int DoNonQuery(string query)
+        {
+			this.LastError = string.Empty;
+
+            if (this.DBConnection == null)
+            {
+                return -1;
+            }
+
+            int rv = 0;
+
+            try
+            {
+                SQLiteCommand command = new SQLiteCommand(query, this.DBConnection);
+                rv = command.ExecuteNonQuery();
+            }
+            catch (Exception exc)
+            {
+				this.LastError = exc.Message;
+                rv = -1;
+            }
+
+            return rv;
+        }
+
+        public int DoNonQuery(string query, params string[] args) => this.DoNonQuery(prepareQuery(query, args));
+
+        public bool HasTable(string tableName)
+        {
+			this.LastError = string.Empty;
+
+            if (this.DBConnection == null)
+            {
+                return false;
+            }
+
+            int rv = this.DoQueryCount("SELECT 1 FROM sqlite_master WHERE type='table' AND name='" + escapeSQL(tableName) + "'");
+
+            return (rv > 0);
+        }
+
+        public bool HasRequiredTables()
+        {
+            bool rv = true;
+            foreach (string tbl in requiredTableList)
+            {
+                if (string.IsNullOrEmpty(tbl))
+                {
+                    continue;
+                }
+
+                if (!this.HasTable(tbl))
+                {
+                    rv = false;
+                    break;
+                }
+            }
+
+            return rv;
+        }
+
+		public bool SetConfig(string name, bool value) => this.SetConfig(name, (value ? "1" : "0"));
+
+		public bool SetConfig(string name, int value) => this.SetConfig(name, value.ToString());
+
+		public bool SetConfig(string name, string value)
+        {
+            prepareAppSettings();
+
+            string sql = string.Empty;
+            int rv = this.DoQueryCount("SELECT 1 FROM " + appSettingsTableName + " WHERE cfg_name='" + escapeSQL(name) + "'");
+            if (rv <= 0)
+            {
+                sql = "INSERT INTO " + appSettingsTableName + " (cfg_name, cfg_value) VALUES ('[^1]', '[^2]');";
+            }
+            else
+            {
+                sql = "UPDATE " + appSettingsTableName + " SET cfg_value='[^2]' WHERE cfg_name='[^1]';";
+            }
+
+            sql = prepareQuery(sql, new string[] { name, value });
+
+            return this.DoNonQuery(sql) > 0;
+        }
+
+        public string GetConfig(string name, string defaultValue = null)
+        {
+            prepareAppSettings();
+
+            bool rv = this.DoQueryExist("SELECT 1 FROM " + appSettingsTableName + " WHERE cfg_name='" + escapeSQL(name) + "';");
+            if (!rv)
+            {
+                return defaultValue;
+            }
+
+            return this.DoQuerySingle("SELECT cfg_value FROM " + appSettingsTableName + " WHERE cfg_name='" + escapeSQL(name) + "';");
+        }
+
+		public int GetIntConfig(string name, int defaultValue = 0)
+		{
+			string rv = this.GetConfig(name);
+			if (string.IsNullOrWhiteSpace(rv))
+			{
+				return defaultValue;
+			}
+
+			int n;
+			if (!int.TryParse(rv, out n))
+			{
+				n = defaultValue;
+			}
+
+			return n;
+		}
+
+		public bool GetBoolConfig(string name, bool defaultValue = false)
+		{
+			string rv = this.GetConfig(name);
+			if (string.IsNullOrWhiteSpace(rv))
+			{
+				return defaultValue;
+			}
+
+			if (rv.Equals("1"))
+			{
+				return true;
+			}
+
+			if (rv.Equals("true", StringComparison.CurrentCultureIgnoreCase))
+			{
+				return true;
+			}
+
+			return false;
+		}
+
+		protected bool create(string filename, bool overwriteFile, string password)
+		{
+			this.LastError = string.Empty;
+
+			if (File.Exists(filename))
+			{
+				if (overwriteFile)
+				{
+					try
+					{
+						File.Delete(filename);
+					}
+					catch (Exception exc)
+					{
+						this.LastError = exc.Message;
+
+						return false;
+					}
+
+					try
+					{
+						SQLiteConnection.CreateFile(filename);
+					}
+					catch (Exception exc)
+					{
+						this.LastError = exc.Message;
+
+						return false;
+					}
+
+					return this.LoadFile(filename, password);
+				}
+				else
+				{
+					return this.LoadFile(filename, password);
+				}
+			}
+			else
+			{
+				try
+				{
+					SQLiteConnection.CreateFile(filename);
+				}
+				catch (Exception exc)
+				{
+					this.LastError = exc.Message;
+
+					return false;
+				}
+
+				return this.LoadFile(filename, password);
+			}
+		}
+
+		protected string prepareQuery(string query, params string[] arguments)
+		{
+			string rv = query;
+
+			if (string.IsNullOrWhiteSpace(rv))
+			{
+				return string.Empty;
+			}
+
+			for (int i = 0; i < arguments.Length; i++)
+			{
+				rv = rv.Replace("[^" + (i + 1).ToString() + "]", escapeSQL(arguments[i]));
+			}
+
+			return rv;
+		}
+
+		protected string escapeSQL(string q) => q.Replace("'", "''").Trim();
+
+		protected string escapeValue(string text) => text.Replace("\"", "\\\"").Replace("\t", "\\t").Replace("\r", " \\r").Replace("\n", "\\n");
+
+		protected string encode64(string text) => Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(text));
+
+		protected bool prepareAppSettings()
+		{
+			if (this.HasTable(appSettingsTableName))
+			{
+				return true;
+			}
+
+			int rv = this.DoNonQuery("CREATE TABLE " + appSettingsTableName + " (cfg_name TEXT, cfg_value TEXT)");
+
+			return rv > 0;
+		}
+
+		protected virtual bool prepareDatabase()
+        {
+            return true;
+        }
+    }
+}