超级简单：一个简单的SQL工具-BuildQuery

/Files/zhuqil/BuildQuery.rar

BuildQuery类是能快速，容易地构建一个复杂的INSERT或者UPDATE 的SQL查询语句。这个类将接收的一些参数，输出有效的SQL语句。它有一个方法能刷新内部数据，因此这个类可以无数次使用，而无需反复创建和销毁实例对象。Buid，IDSettings，和FlushAllData 方法用于设置数据。 Insert, Update, 和Delete 方法用于处理数据。只有 Build 和IDSettings带参数。

代码

   public class BuildQuery
    {
        #region Class Variables
        int numFieldsCount, dicpos;
        Dictionary<string, string> dicFields = new Dictionary<string, string>();
        Dictionary<string, string> dicData = new Dictionary<string, string>();
        Dictionary<string, bool> dicQuotes = new Dictionary<string, bool>();
        List<string> listIDFields = new List<string>();
        List<string> listIDValues = new List<string>();
        List<bool> listIDQuotes = new List<bool>();
        List<string> listIDOperators = new List<string>();
        Boolean IdentityCheck;
        string strTable;
        #endregion

        #region Constructor
        /// <summary>
        /// Creates an instance of this class.
        /// </summary>
        public BuildQuery()
        {
        }
        #endregion

        #region Properties
        /// <summary>
        /// Gets or sets the table that the resulting query will work with.
        /// </summary>
        public string Table
        {
            get
            {
                return strTable;
            }
            set
            {
                strTable = value;
            }
        }

        /// <summary>
        /// Gets or sets whether the query is set to return a new identity value.
        /// </summary>
        public bool GetIdentity
        {
            get
            {
                return IdentityCheck;
            }
            set
            {
                IdentityCheck = value;
            }
        }
        #endregion

        #region Methods
        /// <summary>
        /// Clears all of the internal dictionaries so that a new query can be created.
        /// </summary>
        public void FlushAllData()
        {
            numFieldsCount = 0;
            dicpos = 0;
            dicFields.Clear();
            dicData.Clear();
            dicQuotes.Clear();
            listIDFields.Clear();
            listIDValues.Clear();
            listIDQuotes.Clear();
            listIDOperators.Clear();
        }

        /// <summary>
        /// Adds data to the query.
        /// </summary>
        /// <param name="InputField">String value containing the column in which the data will appear.</param>
        /// <param name="InputData">String value containing the data that is to be used.</param>
        /// <param name="InputQuotes">Boolean value indicating whether the data should be surrounded by quotes.</param>
        public void Build(string InputField, string InputData, bool InputQuotes)
        {
            if (!(dicFields.ContainsKey(InputField)))
            {
                dicFields.Add(InputField, InputField);
                dicData.Add(InputField, InputData);
                dicQuotes.Add(InputField, InputQuotes);
            }
            else
            {
                dicData[InputField] = InputData;
                dicQuotes[InputField] = InputQuotes;
            }
        }

        /// <summary>
        /// Sets the WHERE portion of the query (if applicable) using the specified operator (default is "=".)
        /// </summary>
        /// <param name="IDField">String containing the column to be used.</param>
        /// <param name="IDValue">String containing the value to be used.</param>
        /// <param name="IDQuotes">Boolean indicating whether the value should have quotes around it.</param>
        public void IDSettings(string IDField, string IDValue, bool IDQuotes)
        {
            listIDFields.Add(IDField);
            listIDValues.Add(IDValue);
            listIDQuotes.Add(IDQuotes);
            listIDOperators.Add("=");
        }

        /// <summary>
        /// Sets the WHERE portion of the query (if applicable) using the specified operator (default is "=".)
        /// </summary>
        /// <param name="IDField">String containing the column to be used.</param>
        /// <param name="IDValue">String containing the value to be used.</param>
        /// <param name="IDQuotes">Boolean indicating whether the value should have quotes around it.</param>
        /// <param name="IDOperator">String containing the logic operator to be used in place of the default.</param>
        public void IDSettings(string IDField, string IDValue, bool IDQuotes, string IDOperator)
        {
            listIDFields.Add(IDField);
            listIDValues.Add(IDValue);
            listIDQuotes.Add(IDQuotes);
            listIDOperators.Add(IDOperator);
        }

        /// <summary>
        /// Returns an Input query using the data provided.
        /// </summary>
        public string Insert()
        {
            StringBuilder InsertString = new StringBuilder();
            dicpos = 0;
            numFieldsCount = dicData.Count;
            InsertString.AppendFormat("INSERT INTO {0} (", strTable);
            //Put all of the fields into the query
            foreach (KeyValuePair<string, string> I in dicFields)
            {
                InsertString.Append(I.Value);
                dicpos++;
                if (dicpos + 1 <= numFieldsCount)
                {
                    InsertString.Append(", ");
                }
            }
            dicpos = 0;
            InsertString.Append(") VALUES (");
            //Put all of the data into the query
            foreach (KeyValuePair<string, string> K in dicData)
            {
                if (dicQuotes[K.Key])
                {
                    InsertString.Append("'");
                }
                InsertString.Append(dicData[K.Key]);
                if (dicQuotes[K.Key])
                {
                    InsertString.Append("'");
                }
                dicpos++;
                if (dicpos + 1 <= numFieldsCount)
                {
                    InsertString.Append(", ");
                }
            }
            InsertString.Append(")");
            if (IdentityCheck)
            {
                InsertString.AppendFormat("SET NOCOUNT ON;{0};SELECT @@Identity As LastID", InsertString.ToString());
            }
            return InsertString.ToString();
        }

        /// <summary>
        /// Returns an Update query using the data provided.
        /// </summary>
        public string Update()
        {
            StringBuilder UpdateString = new StringBuilder();
            dicpos = 0;
            numFieldsCount = dicData.Count;
            UpdateString.AppendFormat("UPDATE {0} SET ", strTable);
            //Match up fields and data
            foreach (KeyValuePair<string, string> I in dicFields)
            {
                UpdateString.AppendFormat("{0} = ", I.Value);
                if (dicQuotes[I.Key])
                {
                    UpdateString.Append("'");
                }
                UpdateString.Append(dicData[I.Key]);
                if (dicQuotes[I.Key])
                {
                    UpdateString.Append("'");
                }
                dicpos++;
                if (dicpos + 1 <= numFieldsCount)
                {
                    UpdateString.Append(", ");
                }
            }
            UpdateString.Append(" WHERE ");
            int Conditions = 0;
            for (int IDCount = 0; IDCount < listIDFields.Count; IDCount++)
            {
                if (Conditions > 0)
                {
                    UpdateString.Append(" AND ");
                }
                UpdateString.AppendFormat("{0} {1}", listIDFields[IDCount], listIDOperators[IDCount]);
                if (listIDQuotes[IDCount])
                {
                    UpdateString.Append("'");
                }
                UpdateString.Append(listIDValues[IDCount]);
                if (listIDQuotes[IDCount])
                {
                    UpdateString.Append("'");
                }
                Conditions++;
            }
            return UpdateString.ToString();
        }

        /// <summary>
        /// Returns a Delete query using the data provided.
        /// </summary>
        public string Delete()
        {
            StringBuilder DeleteString = new StringBuilder();
            DeleteString.AppendFormat("DELETE FROM {0} WHERE ", strTable);
            int Conditions = 0;
            for (int IDCount = 0; IDCount < listIDFields.Count; IDCount++)
            {
                if (Conditions > 0)
                {
                    DeleteString.Append(" AND ");
                }
                DeleteString.AppendFormat("{0} {1}", listIDFields[IDCount], listIDOperators[IDCount]);
                if (listIDQuotes[IDCount])
                {
                    DeleteString.Append("'");
                }
                DeleteString.Append(listIDValues[IDCount]);
                if (listIDQuotes[IDCount])
                {
                    DeleteString.Append("'");
                }
                Conditions++;
            }
            return DeleteString.ToString();
        }
        #endregion
    }

BuildQuery类的Build是用来接收查询字段及其值，以及对数据进行处理。这个方法有三个参数，可以如下调用：

obj.Build(InputField, InputData, InputQuotes);

InputField - 字符串值，包含显示的列。
InputData - 字符串值包含被使用的数据。
InputQuotes - 布尔值，表示数据是否应该用引号。

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyField = "Name";
MyData = "John Smith";
MyQuotes = true;
MyQuery.Build(MyField, MyData, MyQuotes);

BuildQuery的FlushAllData 方法是用来清除通过Build存储的所有数据。FlushAllData 将能如下调用：

obj.FlushAllData()

例子：

代码

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyQuery.Table = "MyTable";
MyQuery.Build(MyField, MyData, MyQuotes);
strQuery = MyQuery.Insert;
MyQuery.FlushAllData();
//The object is now ready to work on a different set of data

BuildQuery 的IDSettings方法将用来设置 UPDATE 或者DELETE 得where条件。基本的IDSettings方法有三个参数，还有一个四个参数的重载。它能被如下调用：

obj.IDSettings(IDField, IDValue, IDQuotes);

或者：

obj.IDSettings(IDField, IDValue, IDQuotes, IDOperator);

IDField - 包含了使用列的字符串。
IDValue - 包含值的字符串。
IDQuotes - 布尔值，值是否带引号。
IDOperator - 字符串包含逻辑操作符它将取代默认的'='。

代码

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyField = "Name";
MyData = "John Smith";
MyQuotes = true;
MyOperator = ">=";
MyQuery.IDSettings(MyField, MyData, MyQuotes, MyOperator);

BuildQuery 的Insert方法将产生一条准备在数据库中执行的有效地INSERT查询语句。这个方法需要设置Table属性。并至少有一个实例生成方法已被成功调用。Insert能如下使用:

obj.Insert();

例子：

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyQuery.Table = "MyTable";
MyQuery.Build(MyField, MyData, MyQuotes);
String strQuery = MyQuery.Insert();

BuildQuery的Update方法用来产生一条准备在数据库中执行的有效地 UPDATE查询语句。这个方法需要设置Table属性。对象实例至少成功调用一次IDSettings方法和Build方法各一次。Update方法能如下使用:

obj.Update();

例子：

代码

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyQuery.Table = "MyTable";
MyQuery.IDSettings("MyID", MyValue, false);
objBuildQuery.Build(MyField, MyData, true);
String strQuery = MyQuery.Update();

BuildQuery的Delete方法用于永久删除从在数据库中指定的表的一个或多个行。这个方法需要设置Table属性。对象实例至少成功调用一次IDSettings方法。Delete方法能如下使用:

obj.Delete();

这个类有两个属性：Table 和GetIdentity，两个属性都是可读可写的

Table 属性用来设置BuildQuery类使用的数据表。直到这个属性有值，否者如果产生查询的方法都会返回一个SQl错误

obj.Table = value;

例子：

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyQuery.Table = "MyTable";

GetIdentity 属性用来得到和设置产生INSERT 查询语句插入数据之后是否返回一个行的标识种子，这个属性默认是false。

obj.GetIdentity = true;

例子：

NoInkSoftware.BuildQuery MyQuery = new NoInkSoftware.BuildQuery();
MyQuery.GetIdentity = true;

参考原文：http://www.codeproject.com/KB/database/buildquery.aspx