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-- GUID primary key - arbitrary unique value for table create table person ( id uniqueIdentifier default (newId()) primary key, firstName varchar(100) not null, lastName varchar(100) not null, dob DateTime not null, ssn varchar(9) not null )

-- natural primary key - using an existing piece of data within the table that uniquely identifies the record create table person ( firstName varchar(100) not null, lastName varchar(100) not null, dob DateTime not null, ssn varchar(9) primary key not null )

-- composite key - using two or more existing columns within a table to create a primary key create table person ( firstName varchar(100) not null, lastName varchar(100) not null, dob DateTime not null, ssn varchar(9) not null, primary key (firstName, lastName, dob) )

ALTER TABLE Person DROP CONSTRAINT pk_PersonSSN

You can use limit to tell the number of records to be fetched, and use offset to tell the number of records to skip before starting to return the records. For Example User.limit(3) #returns first three records It will generate following sql query. "SELECT `users`.* FROM `users` LIMIT 3&q...

To do this you need a reference to the assembly which contains the type. If you have another type available which you know is in the same assembly as the one you want you can do this: typeof(KnownType).Assembly.GetType(typeName); where typeName is the name of the type you are looking for (incl...

Extension methods can be used to "hide" processing of inelegant business rules that would otherwise require cluttering up a calling function with if/then statements. This is similar to and analogous to handling nulls with extension methods. For example, public static class CakeExtensions ...

If you need to write a file using different locale settings to the default, you can use std::locale and std::basic_ios::imbue() to do that for a specific file stream: Guidance for use: You should always apply a local to a stream before opening the file. Once the stream has been imbued you shoul...

Group by is often used with join statement. Let's assume we have two tables. The first one is the table of students: IdFull NameAge1Matt Jones202Frank Blue213Anthony Angel18 Second table is the table of subject each student can take: Subject_IdSubject1Maths2P.E.3Physics And because one student c...

MERGE INTO targetTable USING sourceTable ON (targetTable.PKID = sourceTable.PKID) WHEN MATCHED AND (targetTable.PKID > 100) THEN DELETE WHEN MATCHED AND (targetTable.PKID <= 100) THEN UPDATE SET targetTable.ColumnA = sourceTable.ColumnA, targetTable.Co...

MERGE INTO TargetTable AS Target USING (VALUES (1,'Value1'), (2, 'Value2'), (3,'Value3')) AS Source (PKID, ColumnA) ON Target.PKID = Source.PKID WHEN MATCHED THEN UPDATE SET target.ColumnA= source.ColumnA WHEN NOT MATCHED THEN INSERT (PKID, ColumnA) VALUES (Source.PKID...

SELECT COALESCE(NULL, NULL, 'TechOnTheNet.com', NULL, 'CheckYourMath.com'); Result: 'TechOnTheNet.com' SELECT COALESCE(NULL, 'TechOnTheNet.com', 'CheckYourMath.com'); Result: 'TechOnTheNet.com' SELECT COALESCE(NULL, NULL, 1, 2, 3, NULL, 4); Result: 1

USE msdb Go SELECT dbo.sysjobs.Name AS 'Job Name', 'Job Enabled' = CASE dbo.sysjobs.Enabled WHEN 1 THEN 'Yes' WHEN 0 THEN 'No' END, 'Frequency' = CASE dbo.sysschedules.freq_type WHEN 1 THEN 'Once' WHEN 4 THEN 'Daily' ...

WITHOUT_ARRAY_WRAPPER option in FOR JSON clause will remove array brackets from the JSON output. This is useful if you are returning single row in the query. Note: this option will produce invalid JSON output if more than one row is returned. Input table data (People table) IdNameAge1John232J...

Functions can have optional parameters, for example: function hello($name, $style = 'Formal') { switch ($style) { case 'Formal': print "Good Day $name"; break; case 'Informal': print "Hi $name"; break; ...

Detailed instructions on getting concurrency set up or installed.

LeakCanary is an Open Source Java library to detect memory leaks in your debug builds. Just add the dependencies in the build.gradle: dependencies { debugCompile 'com.squareup.leakcanary:leakcanary-android:1.5.1' releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.5.1' ...

In order for a program to react to a certain signal, other than using default action, custom signal handler can be installed using sigaction. sigaction receives three arguments - signal to act on, pointer to sigaction_t structure which, if not NULL, is describing new behaviour and pointer to sigacti...

SELECT DATE('2003-12-31 01:02:03'); The output will be: 2003-12-31

When rendering a form 'by hand', it can be useful to know if there are fields left to render or not. The function isRendered() from the FormView class returns true if there are still fields left to be rendered to the template. This snippet prints <h3>Extra fields</h3> if there are fiel...