SQL Server數據全同步[終結版]

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經過兩天的同步編寫和測試。出了第一個Release版本號：

1. 本函數僅支持單向同步。即從一個主數據庫想多個從數據庫同步

2.主數據庫的不論什麽增刪改都會同步到全部從數據庫上

3. 最重要的一點：同步數據庫的價值所在：當主數據庫server不可用時，程序能夠使用其它從數據庫或者備用數據庫，這對於未來公有雲和私有雲應用具有重大價值！

代碼：

<span style="font-size:18px;">/// <summary>
        /// Note: for columns, the first string must be primary key name!
        /// </summary>
        /// <param name="server"></param>
        /// <param name="database"></param>
        /// <param name="uid"></param>
        /// <param name="password"></param>
        /// <param name="tableName"></param>
        /// <param name="columns"></param>
        /// <param name="ignoreUpdateColumns"></param>
        /// <param name="ignoreInsertColumns"></param>
        public void BulkUpdateTo(string server, string database, string uid, string password, string tableName, List<string> columns, List<string> ignoreUpdateColumns, List<string> ignoreInsertColumns)
        {
            string primaryKeyName = columns[0];
            string connectionString = "Server=" + server + ";Database=" + database + ";User Id=" + uid + ";Password=" + password;
            // Create destination connection
            SqlConnection destinationConnector = new SqlConnection(connectionString);

            SqlCommand cmd = new SqlCommand("SELECT * FROM " + tableName, destinationConnector);
            // Open source and destination connections.
            this.EnsureConnectionIsOpen();
            destinationConnector.Open();

            Dictionary<int, string> Index_PrimaryKeyValue = new Dictionary<int, string>();

            SqlDataReader readerSource = cmd.ExecuteReader();
            Dictionary<string, Dictionary<string, string>> recordsDest = new Dictionary<string, Dictionary<string, string>>();
            int i = 0;
            while (readerSource.Read())
            {
                Index_PrimaryKeyValue.Add(i, readerSource[primaryKeyName].ToString());
                string recordIndex = Index_PrimaryKeyValue[i];
                recordsDest[recordIndex] = new Dictionary<string, string>();
                foreach (string keyName in columns)
                {
                    recordsDest[recordIndex].Add(keyName, readerSource[keyName].ToString());
                }
                i++;
            }

            // Select data from Products table
            cmd = new SqlCommand("SELECT * FROM " + tableName, mySqlConn);
            // Execute reader
            SqlDataReader reader = cmd.ExecuteReader();
            Dictionary<string, Dictionary<string, string>> recordsSource = new Dictionary<string, Dictionary<string, string>>();

            Dictionary<int, string> Index_PrimaryKeyValue2 = new Dictionary<int, string>();

            int j = 0;
            while (reader.Read())
            {
                Index_PrimaryKeyValue2.Add(j, reader[primaryKeyName].ToString());
                string recordIndex = Index_PrimaryKeyValue2[j];
                recordsSource[recordIndex] = new Dictionary<string, string>();
                foreach (string keyName in columns)
                {
                    recordsSource[recordIndex].Add(keyName, reader[keyName].ToString());
                }
                j++;
            }
            reader.Close();
            readerSource.Close();

            foreach (var record in recordsSource)
            {
                string setScripts = string.Empty;
                string insertKeysScripts = string.Empty;
                string insertValuesScripts = string.Empty;
                int setScriptsIndex = 0;
                int insertScriptsIndex = 0;
                string primaryKeyValue = record.Key;
                if (recordsDest.ContainsKey(primaryKeyValue))
                {
                    foreach (string keyName in columns)
                    {
                        if (!ignoreUpdateColumns.Contains(keyName))
                        {
                            if (recordsDest[primaryKeyValue][keyName] == record.Value[keyName])
                            {
                                //do nothing
                            }
                            else
                            {
                                if (setScriptsIndex == 0)
                                {
                                    setScripts += keyName + "=‘" + recordsSource[primaryKeyValue][keyName] + "‘ ";
                                }
                                else
                                {
                                    setScripts += "," + keyName + "=‘" + recordsSource[primaryKeyValue][keyName] + "‘ ";
                                }
                                setScriptsIndex++;
                            }
                        }
                    }
                }
                else
                {
                    foreach (string keyName in columns)
                    {
                        if (!ignoreInsertColumns.Contains(keyName))
                        {
                            if (insertScriptsIndex == 0)
                            {
                                insertKeysScripts += keyName;
                                insertValuesScripts += "‘" + recordsSource[primaryKeyValue][keyName] + "‘ ";
                            }
                            else
                            {
                                insertKeysScripts += "," + keyName;
                                insertValuesScripts += ",‘" + recordsSource[primaryKeyValue][keyName] + "‘ ";
                            }
                            insertScriptsIndex++;
                        }
                    }
                }

                //update source to dest
                if (setScriptsIndex > 0)
                {
                    cmd = new SqlCommand("Update " + tableName + " set " + setScripts + " where " + primaryKeyName + "=‘" + recordsSource[primaryKeyValue][primaryKeyName] + "‘", destinationConnector);
                    cmd.ExecuteNonQuery();
                }

                //insert source to dest
                if (insertScriptsIndex > 0)
                {
                    cmd = new SqlCommand("insert into " + tableName + " (" + insertKeysScripts + ") values (" + insertValuesScripts + ")", destinationConnector);
                    cmd.ExecuteNonQuery();
                }
            }

            //after update and insert, the count still not match, means we delete some records in source db, then we also need to delete the records in destination db
            foreach (var re in recordsDest)
            {
                //get the delete record primary key value
                if (!recordsSource.ContainsKey(re.Key))
                {
                    cmd = new SqlCommand("delete from " + tableName + " where " + primaryKeyName + "=‘" + re.Value[primaryKeyName].ToString() + "‘", destinationConnector);
                    cmd.ExecuteNonQuery();
                }
            }

            // Close objects
            destinationConnector.Close();
            mySqlConn.Close();
        }</span>

代碼的基礎類其它部分請看下列文章：

1. C#同步SQL Server數據庫中的數據--數據庫同步工具[同步已有的有變化的數據]

2.分析下自己寫的SQL Server同步工具的性能和缺陷

3.C#同步SQL Server數據庫中的數據--數據庫同步工具[同步新數據]

SQL Server數據全同步及價值分析[終結版]