Week 5 – Chap. 5 Data Transfer

• DBAs often must transfer data to and from text files, Excel spreadsheets, Access, Oracle or other SQL Server databases

• This process of transferring data is called migration

• Can be performed using a variety of methods

SQL Server’s Data Migration Tools

1.Data Transformation Services (DTS)

1.Bulk Copy Program(BCP)

1.Transact-SQL Bulk Insert Statement

1.Transact-SQL Select Into Statement

Data Transformation Services (DTS)

• Most common method for data transfer• Easy to use wizard (Start SQL Server

Import and Export Data)• DTS allows changes to data (transformation)

while transferring data• Transfer of data to : Export• Transfer of data from : Import• Can import or export data to / from many

sources (Excel, Oracle, SQL Server, Access)• Migration steps can be saved by DTS as a

package and rerun later

DTS Transformation of Data

• Mapping Data Types 1.You can specify how data is formatted

between source and destination2.You can specify how data is modified

between source and destination

• Integrating and Consolidating data 1.You can combine data2.You can summarize data vertically and

horizontally

DTS Packages

• A set of DTS migration steps can be stored as a package

• Packages can be saved to Database files or even in Microsoft Repository Feature

• Packages consist of: • Connections to Data Sources and

Destinations• Tasks – Commands to transfer data,

edit data, …• Workflow – Precedence constraints

for tasks

DTS Package: Connections

Connection is between Source and Destination Data.

DTS Package: Tasks

• A Task is a unit of work

• A Task could:

• Execute a Transact SQL Statement

• Execute a Script

• Launch an external application

• Copy SQL Server objects

• Execute and retrieve results from a DTS Package

DTS Package : Workflow

• Workflow links tasks

• Workflow constraints coordinate flow of control and execution of steps in the DTS Package by precedence:

Precedence constraint

Description

On Success Requires a successful step before execution

On Completion Executes automatically after another step

On Failure Executes when there is a failure

Workflow Order of Execution

Sequence Steps must execute in sequence

Parallel Multiple steps can execute in parallel to improve performance

Combination Steps use a combination of sequential and parallel execution

Workflow Steps Priority

By default all threads have the same priority. But you can change default priority for a step to:

• Idle• Normal • High

Package Scheduling, Execution

Ways to execute a DTS Package:

•Use SQL Enterprise Manager

•Use dtsrun command prompt utility

Ways to Schedule a DTS Package:

•Use DTS import/export wizard when saving to the msdb database

•Use SQL Server Enterprise Manager when you use dtsrun command prompt utility.

DTS Designer

DTS Designer allows experienced Database Administrators to import and export data, transform data and define complex workflows for heterogeneous data from multiple sources

DTS Object Transfer

The Copy SQL Server Object task in both the DTS Import/Export Wizard and in DTS Designer allows easy transfer of database objects between SQL Server Databases.

Objects to be transferred can include tables, views, stored procedures, defaults, rules, user-defined data types, logins, users, roles and constraints

You can transfer all objects in a database or only a subset using this task.

Bulk Copy Program(BCP)

• Bulk Copy Program is performed from O/S command prompt

• Allows import or export of data from/to a text file or a binary file

• The data migrated can be a table or a SQL query result.

• BCP can bypass transaction log files, which improves speed but can compromise recovery

• Always backup database before and after BCP operation

BCP (ctd)

• BCP can create a format file to manipulate data

• BCP is normally an automated process

BCP Export Example

BCP Import Example

BULK INSERT

• A Transact-SQL command that can read a text file or native SQL Server file into an existing table or view

• Can also use a format file (as BCP utility can)

• Commands can be saved to a script

• Scripts can be automated by using osql commands

BULK INSERT (ctd)

• Fastest method of data transfer, because a session doesn’t have to be started for each data transfer

• Database should be backed up after this operation

• Used for copying operations in which performance is the most important consideration

• Can’t transform data using this method

BULK INSERT Example

 

USE pubsGOTRUNCATE TABLE authors2GOBULK INSERT authors2 from "c:\temp\authors2.csv"GOSELECT * FROM authors2GO

SELECT INTO

• SELECT INTO statement copies data from one table to another

• Tables can be on the same SQL Server or linked SQL servers or on different types of servers using distributed queries

• SELECT INTO operates just like Bulk Insert except it can’t read from an external file

• SELECT INTO can also create the destination table automatically before copying the data

SELECT INTO - EXAMPLE

USE pubsGODROP TABLE authors2GOSELECT * INTO authors2 from authorsGOSELECT * FROM authors2GO

Lab Exercises

1.Export data using Enterprise Manager

2. Import data using Enterprise Manager

3.Truncate table from command line

4.Create Export text file from command line

5. Import data from command line

6.Bulk Insert

7.Select Into

8.Schedule a Package