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jQuery Data Table provides export buttons with the help of which we can make a structure like the following −Export PDFExport CSVExport HTMLExport ExcelFor this, we need to write code −var tbl = $('#extable').DataTable({ dom: 'export', buttons: [ { extend: 'collection', text: 'Export', buttons: [ 'csvHtml5', ' pdfHtml5', 'copyHtml5', 'excelHtml5' ] } ] });
To understand error 1452, first we need to create a table and relate that to another table with the help of a foreign key constraint.Creating the first table −mysql> CREATE table ForeignTable -> ( -> id int, -> name varchar(200), -> Fk_pk int -> ); Query OK, 0 rows affected (0.43 sec)After creating the first table successfully, we will create the second table −mysql> CREATE table primaryTable1 -> ( -> Fk_pk int, -> DeptName varchar(200), -> Primary key(Fk_pk) -> ); Query OK, 0 rows affected (0.48 sec)Now, we have created both tables. Then both the tables are related with the ... Read More
Unknown gaps between elements in flexbox are due to margin collapsing of the header to the bar division. To resolve this −Either Margin is reset to 0 for header or Border is added to the bar.Padding can be done to bar by adding property padding: 10px to bar. Try the following code snippet to resolve the unknown gap problem −.bar { background: yellow; color: gray; height: 250px; padding: 10px; text-align: center; }
The schema_name command is used to check if a MySQL database exists or not. The syntax of this command is as follows −select schema_name from information_schema.schemata where schema_name = 'database name';Now, the above command is used to check whether the database exists or not. The query for that is as follows −Case 1 − The database exists.mysql> select schema_name from information_schema.schemata where schema_name = 'business'; The output obtained is as follows −+-------------+ | SCHEMA_NAME | +-------------+ | business | +-------------+ 1 row in set (0.00 sec)Case 2 − The database does not exist.mysql> select schema_name from information_schema.schemata ... Read More
Posts can be selected using div with ‘id=post’. This will select all div elements with an id which contains a value in quotes.We can use either −div[id*='post-'] { ... } or div[id^='post-'] { ... }.div[id*='post-'] { ... } will select all div elements with id which is having all values in quotes.Or we can use,div[id^='post-'] { ... }This will select all div elements with an id which started with quotes.
Use the columns property to set columns with CSS. You can try to run the following code to implement the columns property:ExampleLive Demo .demo { column-rule-color: gray; columns: 100px 4; column-rule-style: dashed; } This is demo text. This is demo text. This is demo text. This is demo text. ... Read More
The arc() function has the following definition that shows the usage of start and ends angle −arc(x, y, radius, startAngle, endAngle, anticlockwise)This method has the following parameters −x and y are coordinates of the circle’s center.Radius is the circle radiusStartAngle and EndAngle define the start and endpoints of the arc in radians. Starting and closing angles are measured from the horizontal i.e. x-axisAnticlockwise is the Boolean value which when true draws arc anticlockwise otherwise in a clockwise direction.
When we draw anything on Canvas, it keeps no memory of anything that was drawn. While drawing we need to keep track of all the necessary information yourself as we draw. Therefore, it is not feasible to get value from HTML5 canvas to JavaScript as it keeps no memory. It just draws like this −On adding a function for button and clicking on it, you won’t be able to get what you want − You will not be able to get those values from the canvas since the canvas is just a bitmap.
The auto_increment is a default property that automatically increments the newly added record by 1. The auto_increment can be changed from the beginning as well. The procedure for that is given below −First, a table is created.mysql> CREATE table DemoAuto -> ( -> id int auto_increment, -> name varchar(100), -> primary key(id) -> ); Query OK, 0 rows affected (0.47 sec)After that the alter table command is used to change the starting number of auto_incremnt which starts from 1 by default. The starting value is changed to 100.mysql> alter table DemoAuto auto_increment = 100; Query OK, 0 rows affected (0.24 ... Read More
The Web Audio API is used to control audio, which allows you to choose audio sources. You can also add effects; create audio visualizations, panning, etc.ExampleYou can try to run the following code snippet to generate sound −// use one context per document. Here we are creating one context for one document. You can create for other documents also var context = new (window.AudioContext || window.webkitAudioContext)(); // oscillator var os = context.createOscillator(); os.type = 'sine'; // sine is the default. So you can also use square, saw tooth, triangle os.frequency.value = 500; // setting the frequency Hz os.connect(context.destination); ... Read More