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SqlBulkCopy.WriteToServer has 4 overloads:
SqlBulkCopy.WriteToServer (DataRow[])
Copies all rows from the supplied DataRow array to a destination table specified by the
DestinationTableName property of the SqlBulkCopy object.
SqlBulkCopy.WriteToServer (DataTable)
Copies all rows in the supplied DataTable to a destination table specified by the
DestinationTableName property of the SqlBulkCopy object.
SqlBulkCopy.WriteToServer (IDataReader)
Copies all rows in the supplied IDataReader to a destination table specified by the
DestinationTableName property of the SqlBulkCopy object.
SqlBulkCopy.WriteToServer (DataTable, DataRowState)
Copies only rows that match the supplied row state in the supplied DataTable to a
destination table specified by the DestinationTableName property of the SqlBulkCopy object.
When importing text files with this method you have to create a DataTable first, import the text file
to the created DataTable and then write this DataTable to server.
With this we‘re acctually performing 2 tasks in .net:
1. Fill data from text file to DataTable in memory
2. Fill data from DataTable in memory to SQL server
Compared to SQL servers native bulk import methods where we just import the text file directly.
I used the same file and the same table structure as in previous bulk import methods described in Last.
The time it took to complete the whole process was around 30 seconds.
This is the code i used for import:
private void StartImport() { Stopwatch sw = new Stopwatch(); sw.Start(); SqlBulkCopy bulkCopy = new SqlBulkCopy("Server=ServerName;Database=test;Trusted_Connection=True;", SqlBulkCopyOptions.TableLock); bulkCopy.DestinationTableName = "dbo.testSQLBulkCopy"; bulkCopy.WriteToServer(CreateDataTableFromFile()); sw.Stop(); txtResult.Text = (sw.ElapsedMilliseconds/1000.00).ToString(); } private DataTable CreateDataTableFromFile() { DataTable dt = new DataTable(); DataColumn dc; DataRow dr; dc = new DataColumn(); dc.DataType = System.Type.GetType("System.Int32"); dc.ColumnName = "c1"; dc.Unique = false; dt.Columns.Add(dc); dc = new DataColumn(); dc.DataType = System.Type.GetType("System.Int32"); dc.ColumnName = "c2"; dc.Unique = false; dt.Columns.Add(dc); dc = new DataColumn(); dc.DataType = System.Type.GetType("System.Int32"); dc.ColumnName = "c3"; dc.Unique = false; dt.Columns.Add(dc); dc = new DataColumn(); dc.DataType = System.Type.GetType("System.Int32"); dc.ColumnName = "c4"; dc.Unique = false; dt.Columns.Add(dc); StreamReader sr = new StreamReader(@"d:\work\test.txt"); string input; while ((input = sr.ReadLine()) != null) { string[] s = input.Split(new char[] { ‘|‘ }); dr = dt.NewRow(); dr["c1"] = s[0]; dr["c2"] = s[1]; dr["c3"] = s[2]; dr["c4"] = s[3]; dt.Rows.Add(dr); } sr.Close(); return dt; }
Bulk Import Methods are ad below..:-
1. BCP
2. Bulk Insert
3. OpenRowset with BULK option
4. SQL Server Integration Services - SSIS
I ran each bulk import option 12 times, disregarded best and worst time and averaged the remaining ten times.
Results are:
| 1. | SSIS - FastParse ON | = | 7322 ms |
| 2. | SSIS - FastParse OFF | = | 8387 ms |
| 3. | Bulk Insert | = | 10534 ms |
| 4. | OpenRowset | = | 10687 ms |
| 5. | BCP | = | 14922 ms |
So speed gain is quite large when using FastParse.
I was also surprised that SSIS - FastParse OFF method was faster by 20% to Bulk Insert and OpenRowset
and around 40% faster than BCP.
Since my desire was to test how much faster is importing flat files when FastParse option is used
I created a text file containing 4 bigint columns with 1,000,000 rows.
The script i used to create a sample test file in C#:
string str; StreamWriter sw = new StreamWriter(@"d:\work\test.txt"); for (int i = 1; i <= 1000000; i++) { str = i.ToString() + "|" + Convert.ToString(i * 2) + "|" + Convert.ToString(i * 3) + "|" + Convert.ToString(i / 2); sw.WriteLine(str); } sw.Close();
I also created this format file for use with BCP, Bulk Insert and OpenRowset:
9.0 4 1 SQLBIGINT 0 8 "|" 1 c1 "" 2 SQLBIGINT 0 8 "|" 2 c2 "" 3 SQLBIGINT 0 8 "|" 3 c3 "" 4 SQLBIGINT 0 8 "\r\n" 4 c4 ""
SSIS Package was a very simple one with a Flat File source and SQL server destination objects.
The sql script i used is:
create database test go use test go -- ran for each SSIS test run -- SSIS data type for each column was "eight-byte signed integer [DT_I8]" drop table testFastParse create table testFastParse(c1 bigint, c2 bigint, c3 bigint, c4 bigint) go -- insert data using OPENROWSET create table testOpenRowset(c1 bigint, c2 bigint, c3 bigint, c4 bigint) go DBCC DROPCLEANBUFFERS declare @start datetime set @start = getdate() insert into testOpenRowset(c1, c2, c3, c4) SELECT t1.c1, t1.c2, t1.c3, t1.c4 FROM OPENROWSET( BULK ‘d:\work\test.txt‘, FORMATFILE = ‘d:\work\testImport-f-n.Fmt‘) AS t1(c1, c2, c3, c4); select getdate() - @start as ElapsedTime drop table testOpenRowset -- insert data using Bulk Insert create table testBulkInsert(c1 bigint, c2 bigint, c3 bigint, c4 bigint) go DBCC DROPCLEANBUFFERS declare @start datetime set @start = getdate() BULK INSERT testBulkInsert FROM ‘d:\work\test.txt‘ WITH (FORMATFILE=‘d:\work\testImport-f-n.Fmt‘) select getdate() - @start as ElapsedTime drop table testBulkInsert go -- insert data using BCP create table testBCP(c1 bigint, c2 bigint, c3 bigint, c4 bigint) go DBCC DROPCLEANBUFFERS exec master..xp_cmdshell ‘bcp test.dbo.testBCP in d:\work\test.txt -T -b1000000 -fd:\work\testImport-f-n.Fmt‘ drop table testBCP go drop database test
C# .NET - Sql Bulk Insert from multiple delimited Textfile using c#.net
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原文地址：http://www.cnblogs.com/itelite/p/4042259.html
