Tutorial by Examples: d

According to the documentation under ?@async, "@async wraps an expression in a Task." What this means is that for whatever falls within its scope, Julia will start this task running but then proceed to whatever comes next in the script without waiting for the task to complete. Thus, for...

When you first start Julia, by default, there will only be a single process running and available to give work to. You can verify this using: julia> nprocs() 1 In order to take advantage of parallel processing, you must first add additional workers who will then be available to do work that...

SELECT s.name AS [schema], t.object_id AS [table_object_id], t.name AS [table_name], c.column_id, c.name AS [column_name], i.name AS [index_name], i.type_desc AS [index_type] FROM sys.schemas AS s INNER JOIN sys.tables AS t ON s.schema_id = t.schema_id I...

Whenever you change data, in a Data Manipulation Language(DML) command, you can wrap your changes in a transaction. DML includes UPDATE, TRUNCATE, INSERT and DELETE. One of the ways that you can make sure that you're changing the right data would be to use a transaction. DML changes will take a loc...

To create a view with an index, the view must be created using the WITH SCHEMABINDING keywords: CREATE VIEW view_EmployeeInfo WITH SCHEMABINDING AS SELECT EmployeeID, FirstName, LastName, HireDate FROM [dbo].Employee GO Any clustered or non-clustered ...

Stored procedures can return values using the OUTPUT keyword in its parameter list. Creating a stored procedure with a single out parameter CREATE PROCEDURE SprocWithOutParams ( @InParam VARCHAR(30), @OutParam VARCHAR(30) OUTPUT ) AS BEGIN SELECT @OutParam = @InParam + ' must co...

-- Identity primary key - unique arbitrary increment number create table person ( id int identity(1,1) primary key not null, firstName varchar(100) not null, lastName varchar(100) not null, dob DateTime not null, ssn varchar(9) not null )

-- 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 )

ALTER TABLE person ADD CONSTRAINT pk_PersonSSN PRIMARY KEY (ssn) Note, if the primary key column (in this case ssn) has more than one row with the same candidate key, the above statement will fail, as primary key values must be unique.

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...

AppDomain.UnhandledException This event provides notification of uncaught exceptions.It allows the application to log information about the exception before the system default handler reports the exception to the user and terminates the application.If sufficient information about the state of the a...

There are several to evaluate a certain expression when debugging a Java application. 1. Manually inspecting an expression When the program execution is suspended at a certain line (either due to a breakpoint or manually stepping through the debugger), you can manually evaluate an expression by se...

n order to debug a remote Java application, it should be launched with some extra arguments to instruct the JVM to execute it in debug mode. This is done as follows: java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000 -jar sampleApp.jar The above command tells the JVM to s...

The using keyword ensures that the resource defined within the statement only exists within the scope of the statement itself. Any resources defined within the statement must implement the IDisposable interface. These are incredibly important when dealing with any connections that implement the IDi...

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...

Linux running systemd, like Ubuntu 16.04, adding -H tcp://0.0.0.0:2375 to /etc/default/docker does not have the effect it used to. Instead, create a file called /etc/systemd/system/docker-tcp.socket to make docker available on a TCP socket on port 4243: [Unit] Description=Docker Socket for the AP...

By default, a new class module is a Private class, so it is only available for instantiation and use within the VBProject in which it is defined. You can declare, instantiate and use the class anywhere in the same project: 'Class List has Instancing set to Private 'In any other module in the SAME ...

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...