Tuesday, July 25, 2017

Generate database object scripts with mulit-platform tool mssql-scripts

In your SSMS on your computer you can use the Generate Scripts drop-down
menu to create scripts for database objects as shown here for Northwind database on SQL Server 2016 SP1.


The above is for SQL Server on Windows Platform. However, mssql-scripts tool provide the same functionality as Generate Scripts wizard on SQL Servers on Linux and macOS. Of course mssql-scripts would work on Windows as well.

Using mssql-scripts based on Python you can generate T-SQL scripts for objects on SQL Servers, Azure SQL database and Azure SQL Data Warehouse. The generated script is saved to a .sql file or on Linux can be piped to standard Unix utilities (sed, awk and grep). The scripts can be checked into source control systems as well.

The source code for mssql-scripter is found here:
https://github.com/Microsoft/sql-xplat-cli

Sunday, July 23, 2017

String function SOUNDEX

Soundex is how a name of a person is coded as used in the census for locating a person. It is based on how a name sounds rather than how it is spelled.

The name of the person is converted into a 4 character code, the first character in the code is the first letter of the person's name capitalized. The next three characters (they are number) that follow the rule stated here.

Rule 1:
For letters B,F,P,V                           use the number 1
For letters C,G,,K,Q,S,X,Z               use the number 2
For letters D,T                                  use the number 3
For letter L                                        use the number 4
For letters M and N                         use the number 5
For letter R                                        use the number 6

Rule2:
Disregard the letters A, E, I, O, U, H, W, Y (unless they are the first character in the name)

Example:
If the person's name is johnson, the first character in the soundex code is J

As to the rest of the characters in the code, using the above rules we have for johnson the Soundex code J525

The Soundex for Johnson is reduced to JNSN since O and H are not counted and N=5 and S=2 and J is the first character.

By the same rule, the Soundex code for Iowa is I000
Get more info from here:
http://www.archives.gov/research/census/soundex.html

and here:
http://www.ironrangeresearchcenter.org/genealogy/help/soundex/index.htm

Usage:



Testing a comparison operator in an SQL Query?

Let us say we want to know if a variable x is greater or less than another variable y. How do we write a query to test it?

One way to do this is as follows:

declare @x int
set @x=5
declare @y int
set @y=10
    IF @x < @y
 print 1
    ELSE
 print 0

Wednesday, July 19, 2017

Regarding ntext, nchar and nvarchar

These are basically used for textual information related data types. There is a strong recommendation not to use ntext as it is not going to be supported.

These are their definitions from Microsoft Documentation.

ntext (National Text):
Variable-length Unicode data with a maximum string length of 2^30 - 1 (1,073,741,823) bytes. Storage size, in bytes, is two times the string length that is entered

nchar [ ( n ) ]
Fixed-length Unicode string data. n defines the string length and must be a value from 1 through 4,000. The storage size is two times n bytes. When the collation code page uses double-byte characters, the storage size is still n bytes. Depending on the string, the storage size of n bytes can be less than the value specified for n. The ISO synonyms for nchar are national char and national character..
1
nvarchar [ ( n | max ) ]
Variable-length Unicode string data. n defines the string length and can be a value from 1 through 4,000. max indicates that the maximum storage size is 2^31-1 bytes (2 GB). The storage size, in bytes, is two times the actual length of data entered + 2 bytes. The ISO synonyms for nvarchar are national char varying and national character varying.

ntext is supposed to be discontinued, but in actuality it is still present as a choice in data types listing even in SQL Server 16.


Sunday, July 16, 2017

Restoring the Northwind database from its backup

A backup of Northwind database was obtained from the Codeplex site and was saved to one of the folders on a Dell computer with Windows 10 OS. The computer also has SQL Server Management Studio (v 17.1). You should be able to restore using the SQL Server Management Studio installed when you installed the SQL Server 2012 Database engine.

Follow these steps to restore the Northwind database to an instance of SQL Server 2012 (x86) installed on the same computer.

Step 1. Start SQL Server Management Studio v17.1 (Run as administrator)

The SSMS is version 17.1 and Hodentek9\PCATT is a SQL Server 2012 Express

Step 2. Right click the Databases node highlighted in the PCATT isntnace as shown.




RestoreDB_01

Step 3: Click Restore Database...

Restore Database window is displayed as shown.


RestoreDB_02

Step 4: The Default Source is Database and it is greyed out as shown. Chnage it to Device. The Restore Database gets changed as shown.


RestoreDB_03

Step 5: Click the ellipsis button along 'Device' in the above image.

Select backup devices window shows on top of Restore Database window as shown.


RestoreDB_04

Step 6: Click Add button in Select backup devices window.
Locate Backup File window gets displayed as shown.


RestoreDB_05

Usually the 'backup files with extension .bak' are found in the following directory in the case of x32 bit SQL Server.
C:\Program Files (x86)\Microsoft SQL Server\MSSQL11.PCATT\MSSQL\Backup

However, for this exercise it is stored in a different location.

Step 7: Now browse to that location and highlight the Northwind.bak (A backup file which came from a Microsoft site) as shown.


RestoreDB_06

Step 8: Click OK. The file path is entered in the Select backup devices window as shown.


RestoreDB_07.png

Step 9: Click OK
You are returned to the Restore Database - Northwind as shown.


RestoreDB_08.png

Step 10: Click OK in the above.

Microsoft SQL Server Managment Studio message reports that the database
'Northwind' restored successfully.


RestoreDB_09.png

Step 11: Click OK to the message. Verify that Northwind database is in the SQL Server 2012 instance Hodentek9\PCATT


RestoreDB_10.png


Bye



Saturday, July 15, 2017

Microsoft SQL Server Management Studio 17.1 is generally available

SSMS Version 17.1 became available in June 2017 and you may want to downladd and install. This version will work with all editions of SQL Server so far (2018 to 2017). However some of the older applications written using older versions may still need older versions of SQL Server Management Studio.

Download the latest version of SQL Server Management Studio (version 17.1) here:

https://docs.microsoft.com/en-us/sql/ssms/download-sql-server-management-studio-ssms

If you had had SSMS version 17.0, you may get a notification as to availability of version 17.1 which should facilitate installing the new version.


You need to restart after installing.




These are the enhancements in this version:

  • Profiler: Help > About now displays release version number (e.g 17.1)
  • Analysis Service users can refresh credentials for their datasources for 1200 TM models and above from the context menu on the datasource
  • Built-in SSIS reports now show logs from SSIS scale-out execution in CTP 2.1
  • SSIS scale-out management application
             View basic information about scale-out master.
             Easily add a Worker to the scale-out deployment.
             View all the scale-out workers and basic information about them, and can also enable or disable them easily.

This version will also have toast notifications when new updates are available. It also has a new stand alone web installer.

Friday, July 14, 2017

New security feature in SQL Server 2016: Dynamic Data Masking

Dynamic Data Masking which is available in SQL Server 2016 allows you provide another level of security to your data, by masking data that you do not want unauthorized (by policies) users to peek into. Data in the database itself is unchanged. SQL Server 2016 has other security features besides dynamic data masking.

Data leaks and hacking has become too common place. SQL Server 2016 provides yet another way to protect data by this new feature, Dynamic Data Masking (DDM).  Developers and administrator should (must) use this feature to mask data from intentional prying eyes.

DDM is a nice feature that you should implement if are dealing with sensitive information (Credit card numbers, Social Security Numbers, etc).

Here is an image of credit card numbers being masked (perhaps not by DDM in this view)



Credit card masking imaged source: http://www.gsapps.com/images/masking2.gif

Read here about masking using JavaScript:

https://stackoverflow.com/questions/25367230/masking-a-social-security-number-input

Do you need special permission to create a table with a dynamic data mask?

No, you do not. Of course you need standard permissions like Create table, Alter on schema permissions.

The Alter Any Mask permission and Alter permission on  a Table are needed, though.

Read more about Dynamic Data Masking here:
https://docs.microsoft.com/en-us/sql/relational-databases/security/dynamic-data-masking