mssql.cs

C# 的地图开发例子（sharp map)

// Copyright 2006 - Morten Nielsen (www.iter.dk)
//
// This file is part of SharpMap.
// SharpMap is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// SharpMap is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with SharpMap; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
using System.Data.SqlClient;
using System.Data;
using SharpMap.Data;
using SharpMap.Data.Providers;
using SharpMap.Converters.WellKnownBinary;

namespace SharpMap.Data.Providers
{
	/// <summary>
	/// Microsoft SQL data provider
	/// </summary>
	/// <remarks>
	/// <para>
	/// The SQL data table MUST contain five data columns: A binary or image column (a Geometry Column) for storing WKB formatted geometries, 
	/// and four real values holding the boundingbox of the geometry. These must be named: Envelope_MinX, Envelope_MinY, Envelope_MaxX and Envelope_MaxY.
	/// Any extra columns will be returns as feature data.
	/// </para>
	/// <para>For creating a valid MS SQL datatable for SharpMap, see <see cref="CreateDataTable"/> 
	/// for creating and uploading a datasource to MS SQL Server.</para>
	/// <example>
	/// Adding a datasource to a layer:
	/// <code lang="C#">
	/// SharpMap.Layers.VectorLayer myLayer = new SharpMap.Layers.VectorLayer("My layer");
	/// string ConnStr = @"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|GeoDatabase.mdf;Integrated Security=True;User Instance=True";
	/// myLayer.DataSource = new SharpMap.Data.Providers.MsSql(ConnStr, "myTable");
	/// </code>
	/// </example>
	/// </remarks>
	[Serializable]
	public class MsSql : IProvider, IDisposable
	{
		/// <summary>
		/// Initializes a new connection to MS Sql Server
		/// </summary>
		/// <param name="ConnectionStr">Connectionstring</param>
		/// <param name="tablename">Name of data table</param>
		/// <param name="geometryColumnName">Name of geometry column</param>
		/// /// <param name="OID_ColumnName">Name of column with unique identifier</param>
		public MsSql(string ConnectionStr, string tablename, string geometryColumnName, string OID_ColumnName)
		{
			this.ConnectionString = ConnectionStr;
			this.Table = tablename;
			this.GeometryColumn = geometryColumnName; //Name of column to store geometry
			this.ObjectIdColumn = OID_ColumnName; //Name of object ID column
		}

		private bool _IsOpen;

		/// <summary>
		/// Returns true if the datasource is currently open
		/// </summary>
		public bool IsOpen
		{
			get { return _IsOpen; }
		}

		/// <summary>
		/// Opens the datasource
		/// </summary>
		public void Open()
		{
			//Don't really do anything. mssql's ConnectionPooling takes over here
			_IsOpen = true;
		}
		/// <summary>
		/// Closes the datasource
		/// </summary>
		public void Close()
		{
			//Don't really do anything. mssql's ConnectionPooling takes over here
			_IsOpen = false;
		}


		#region Disposers and finalizers
		private bool disposed = false;

		/// <summary>
		/// Disposes the object
		/// </summary>
		public void Dispose()
		{
			Dispose(true);
			GC.SuppressFinalize(this);
		}

		internal void Dispose(bool disposing)
		{
			if (!disposed)
			{
				if (disposing)
				{
					//Close();
				}
				disposed = true;
			}
		}

		/// <summary>
		/// Finalizer
		/// </summary>
		~MsSql()
		{
			Dispose();
		}
		#endregion

		private string _ConnectionString;

		/// <summary>
		/// Connectionstring
		/// </summary>
		public string ConnectionString
		{
			get { return _ConnectionString; }
			set { _ConnectionString = value; }
		}

		private string _Table;

		/// <summary>
		/// Data table name
		/// </summary>
		public string Table
		{
			get { return _Table; }
			set { _Table = value; }
		}

		private string _GeometryColumn;

		/// <summary>
		/// Name of geometry column
		/// </summary>
		public string GeometryColumn
		{
			get { return _GeometryColumn; }
			set { _GeometryColumn = value; }
		}

		private string _ObjectIdColumn;

		/// <summary>
		/// Name of column that contains the Object ID
		/// </summary>
		public string ObjectIdColumn
		{
			get { return _ObjectIdColumn; }
			set { _ObjectIdColumn = value; }
		}


		/// <summary>
		/// Returns geometries within the specified bounding box
		/// </summary>
		/// <param name="bbox"></param>
		/// <returns></returns>
		public Collection<Geometries.Geometry> GetGeometriesInView(SharpMap.Geometries.BoundingBox bbox)
		{
			Collection<Geometries.Geometry> features = new Collection<SharpMap.Geometries.Geometry>();
			using (SqlConnection conn = new SqlConnection(_ConnectionString))
			{
				string BoxIntersect = GetBoxClause(bbox);
				
				string strSQL = "SELECT " + this.GeometryColumn + " AS Geom ";
				strSQL += "FROM " + this.Table + " WHERE ";
				strSQL += BoxIntersect;
				if (!String.IsNullOrEmpty(_defintionQuery))
					strSQL += " AND " + this.DefinitionQuery;

				using (SqlCommand command = new SqlCommand(strSQL, conn))
				{
					conn.Open();
					using (SqlDataReader dr = command.ExecuteReader())
					{
						while (dr.Read())
						{
							if (dr[0] != DBNull.Value)
							{
								SharpMap.Geometries.Geometry geom = SharpMap.Converters.WellKnownBinary.GeometryFromWKB.Parse((byte[])dr[0]);
								if (geom != null)
									features.Add(geom);
							}
						}
					}
					conn.Close();
				}
			}
			return features;
		}

		/// <summary>
		/// Returns the geometry corresponding to the Object ID
		/// </summary>
		/// <param name="oid">Object ID</param>
		/// <returns>geometry</returns>
		public SharpMap.Geometries.Geometry GetGeometryByID(uint oid)
		{
			SharpMap.Geometries.Geometry geom = null;
			using (SqlConnection conn = new SqlConnection(_ConnectionString))
			{
				string strSQL = "SELECT " + this.GeometryColumn + " AS Geom FROM " + this.Table + " WHERE " + this.ObjectIdColumn + "='" + oid.ToString() + "'";
				conn.Open();
				using (SqlCommand command = new SqlCommand(strSQL, conn))
				{
					using (SqlDataReader dr = command.ExecuteReader())
					{
						while (dr.Read())
						{
							if (dr[0] != DBNull.Value)
								geom = SharpMap.Converters.WellKnownBinary.GeometryFromWKB.Parse((byte[])dr[0]);
						}
					}
				}
				conn.Close();
			}
			return geom;
		}
		/// <summary>
		/// Returns geometry Object IDs whose bounding box intersects 'bbox'
		/// </summary>
		/// <param name="bbox"></param>
		/// <returns></returns>
		public Collection<uint> GetObjectIDsInView(SharpMap.Geometries.BoundingBox bbox)
		{
			Collection<uint> objectlist = new Collection<uint>();
			using (SqlConnection conn = new SqlConnection(_ConnectionString))
			{
				string strSQL = "SELECT " + this.ObjectIdColumn + " ";
				strSQL += "FROM " + this.Table + " WHERE ";

				strSQL += GetBoxClause(bbox);

				if (!String.IsNullOrEmpty(_defintionQuery))
					strSQL += " AND " + this.DefinitionQuery + " AND ";

				using (SqlCommand command = new SqlCommand(strSQL, conn))
				{
					conn.Open();
					using (SqlDataReader dr = command.ExecuteReader())
					{
						while (dr.Read())
						{
							if (dr[0] != DBNull.Value)
							{
								uint ID = (uint)(int)dr[0];
								objectlist.Add(ID);
							}
						}
					}
					conn.Close();
				}
			}
			return objectlist;
		}

		/// <summary>
		/// Returns the features that intersects with 'geom' [NOT IMPLEMENTED]
		/// </summary>
		/// <param name="geom"></param>
		/// <param name="ds">FeatureDataSet to fill data into</param>
		public void ExecuteIntersectionQuery(SharpMap.Geometries.Geometry geom, FeatureDataSet ds)
		{
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns the number of features in the dataset
		/// </summary>
		/// <returns>number of features</returns>
		public int GetFeatureCount()
		{
			int count = 0;
			using (SqlConnection conn = new SqlConnection(_ConnectionString))
			{
				string strSQL = "SELECT COUNT(*) FROM " + this.Table;
				if (!String.IsNullOrEmpty(_defintionQuery))
					strSQL += " WHERE " + this.DefinitionQuery;
				using (SqlCommand command = new SqlCommand(strSQL, conn))
				{
					conn.Open();
					count = (int)command.ExecuteScalar();
					conn.Close();
				}
			}
			return count;
		}

		private string _defintionQuery;

		/// <summary>
		/// Definition query used for limiting dataset
		/// </summary>
		public string DefinitionQuery
		{
			get { return _defintionQuery; }
			set { _defintionQuery = value; }