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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