[英]SQL bulk copy with mapped columns
我試圖通過映射列名從一個表批量復制到另一個表,因為源和目標可能並不總是具有相同的列。
源可以有 8 列,目標可以有 10 .. 我需要映射列和批量復制。
嘗試了下面的代碼..不起作用..得到錯誤:給定的 ColumnName 'moduleid' 與數據源中的任何列都不匹配。
來源:existingtablecolumnsPresent 有[收集時間],[logtime],[moduleid],[node],[reason],[time],[timestamp],[usecaseid]
目的:dataTable.Columns有[Node],[Time],[Reason],[Moduleid],[Usecaseid]
請指教
public static void BatchBulkCopy(DataTable dataTable, string DestinationTbl, List<string> columnMapping,string filename)
{
var program = new Program();
// Get the DataTable
DataTable dtInsertRows = dataTable;
using (SqlBulkCopy sbc = new SqlBulkCopy(program.connectionStr.ToString()))
{
try {
sbc.DestinationTableName = DestinationTbl.ToLower();
string sourceTableQuery = "Select top 1 * from " + "[" + dataTable.TableName + "]";
DataTable dtSource = SqlHelper.ExecuteDataset(program.connectionStr.ToString(), CommandType.Text, sourceTableQuery).Tables[0];
for (int i = 0; i < dataTable.Columns.Count; i++)
{ //check if destination Column Exists in Source table
if (dtSource.Columns.Cast<DataColumn>().Select(a => "[" + a.ColumnName.ToLower() + "]").Contains(dataTable.Columns[i].ToString().ToLower()))//contain method is not case sensitive
{
List<string> existingtablecolumnsPresent = dtSource.Columns.Cast<DataColumn>().Select(a => "[" + a.ColumnName.ToLower() + "]").Distinct().OrderBy(t => t).ToList();
int sourceColumnIndex = existingtablecolumnsPresent.IndexOf(dataTable.Columns[i].ToString().ToLower());//Once column matched get its index
sbc.ColumnMappings.Add(dtSource.Columns[sourceColumnIndex].ToString(), dtSource.Columns[sourceColumnIndex].ToString());//give coluns name of source table rather then destination table so that it would avoid case sensitivity
}
}
sbc.WriteToServer(dtInsertRows);
sbc.Close();
}
catch (Exception ex)
{
Log.WriteLog("BatchBulkCopy" + " - " + filename, dataTable.TableName, ex.Message.ToString());
// To move a file or folder to a new location:
//if (File.Exists(program.sourceFile + filename))
// System.IO.File.Move(program.sourceFile + filename, program.failedfiles + filename);
}
根據要求(創建一個包含要插入其中的列的數據表 - 將其他列排除在外。確保您遺漏的任何列在表中標記為 NULL 或具有 DEFAULT VALUE 約束(我無法向您展示如何除非你給我看你的桌子,否則不要這樣做);
//This first method is psuedoCode to explain how to create your datatable. You need to do it in the way that makes sense for you.
public DataTable createDataTable(){
List<string> excludedColumns = new List<string>();
excludedColumns.Add("FieldToExclude");
//...
DataTable dt = new DataTable();
foreach(string col in getColumns(myTable)){
if(!excludedColumns.Contains(name)){
DataColumn dC = new DataColumn(name,type);
DataTable.Add(dC);
}
return dt;
}
public List<string> getColumns(string tableName)
{
List<string> ret = new List<string>();
using (SqlConnection conn = getConn())
{
conn.Open();
using (SqlCommand com = conn.CreateCommand())
{
com.CommandText = "select column_Name from information_schema.COLUMNS where table_name = @tab";
com.Parameters.AddWithValue("@tab", tableName);
SqlDataReader read = com.ExecuteReader();
While(read.Read()){
ret.Add(Convert.ToString(read[0]);
}
conn.Close();
}
return ret;
}
//Now, you have a DataTable that has all the columns you want to insert. Map them yourself in code by adding to the appropriate column in your datatable.
public bool isCopyInProgess = false;//not necessary - just part of my code
public void saveDataTable(string tableName, DataTable table)
{
using (SqlConnection conn = getConn())
{
conn.Open();
using (var bulkCopy = new SqlBulkCopy(conn))//, SqlBulkCopyOptions.KeepIdentity))//un-comment if you want to use your own identity column
{
// my DataTable column names match my SQL Column names, so I simply made this loop. However if your column names don't match, just pass in which datatable name matches the SQL column name in Column Mappings
foreach (DataColumn col in table.Columns)
{
//Console.WriteLine("mapping " + col.ColumnName+" ("+does_Column_Exist(col.ColumnName,"Item").ToString()+")");
bulkCopy.ColumnMappings.Add(col.ColumnName, "["+col.ColumnName+"]");
// Console.WriteLine("ok\n");
}
bulkCopy.BulkCopyTimeout = 8000;
bulkCopy.DestinationTableName = tableName;
bulkCopy.BatchSize = 10000;
bulkCopy.EnableStreaming = true;
//bulkCopy.SqlRowsCopied += BulkCopy_SqlRowsCopied;
//bulkCopy.NotifyAfter = 10000;
isCopyInProgess = true;
bulkCopy.WriteToServer(table);
}
conn.Close();
}
}
此外,將其用作您的 bolumn 檢查器:
public bool does_Column_Exist(string colName,string tableName)
{
bool ret = false;
using (SqlConnection conn = getConn())
{
conn.Open();
using (SqlCommand com = conn.CreateCommand())
{
com.CommandText = "select count(*) from information_schema.COLUMNS where column_name = @col and table_name = @tab";
com.Parameters.AddWithValue("@tab", tableName);
com.Parameters.AddWithValue("@col", colName);
ret = Convert.ToInt32(com.ExecuteScalar()) == 0 ? false : true;
}
conn.Close();
}
return ret;
}
為此,您需要 C# 有什么特定原因嗎? 似乎阻力最小的路徑是使用 SQL 來完成這項工作。
INSERT INTO table2
(column_name(s))
SELECT column_name(s)
FROM table1;
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