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COMP233
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- 1how to get values from a URL?use the $_GET method and use the url variable
eg: url: index.html?variable=value
we use $_GET['variable'] to get the value - 2SQL: SELECT statementIs used to query a database.
SELECT * FROM table_name;
SELECT column_name, column_name
FROM table_name;
SELECT * column_name, column_name
FROM table_name
WHERE column_name1 = value1;
column_name2 = value2; - 3the ` <-- Backquote in mySQLSELECT `orderNo`, `customerID` from `order`
- 4mySQL datatypesEach column must have a datatype
eg: VARCHAR, BOOLEAN, CHARACTER - 5Using Select QueriesGets customers who are in Auckland
SELECT `givenName`, `surName`
FROM `customer`
WHERE `city` = `Auckland`;
Order number of orders which have more than 30 items
SELECT `orderNo`
FROM `order`
WHERE `numOfItems` > 30; - 6SELECT DISTINCT `column_name` FROM `table_name`The SELECT DISTINCT query returns all the distinct values
- 7SELECT FROM ORDERwill sort all the data in the column use
ASC|DESC
for ascending|descending order - 8count(*)Returns the number of rows in the result
- 9min(column_name)to get the minimum value in the column
- 10max(column_name)get the maximum value in the column
- 11sum(column_name)get the sum of all the values in the column
- 12avg(column_name)get the average of all the values in the column
- 13Updating the databaseUPDATE table_name
SET column1=value1, column2=value2
WHERE some_column=some_value;
UPDATE `customer`
SET `GivenName` = `Christie`
WHERE `customerID`=1002; - 14mysqli_connect()make a connection to a specified mySQL server using the given username, password and database
- 15mysqli_query()issue an SQL statement
- 16mysqli_fetch_assoc()get one row of results
- 17mysqli_close()close the connection
- 18Retrieving data from a table1.Establish a connection to the database
2.Run a query
3.Receive the data from the query
4.Close the connection - 19How do you establish a connection to the database?$connection = mysqli_connect($servername, $username, $password, $database);
- 20How do you run a query?$result = mysqli_query($conn, $query, $resultmode);
- 21How do you receive the data from the query?$row = mysqli_fetch_assoc($result);
- 22How do you close the connection to the database?mysqli_close($conn);
- 23How do you display the data in a table (php)?';
echo $row['CustomerID']. " ";
echo $row['Surname']. " ";
echo '
';
}
mysqli_close($conn); - 24mysli_connect_error()if the connection cannot be established mysqli_connect will return FALSE. In such a case display an error message to the user
if($conn ==== FALSE) {
die("ERROR".mysqli_connect_error()); - 25Inserting data into a table from php$query = "INSERT INTO `customer`(`customerID`, `Surname`, `Firstname`, `city`, `phone`, `email`) VALUES ($id, $sirname, $firstname, $city, $phone, $email);
- 26Display data in a formif(isset($_GET) {
$variable = $_GET("form_item_name");
} - 27Updating records in a databaseUPDATE.. SET.. WHERE
identify the row to change via the WHERE condition SET a list columnname=value pairs to specify data values - 28DOM?Document Object Model
- 29DOM........Javascript gives you the ability to completely change all aspects of the webpage after it's loaded in the browser.
What gives JS this power over a webpage is the Document-Object-Model(DOM)
DOM is a tree like representation of the webpage along with an API
The W3C defines the DOM as
- a platform and language neutral interface that will allow programs and scripts to dynamically access and update the content, structure and style of documents
A web browser parses the HTML representation of a page and constructs a corresponding representation in the form of an internal data structure
This structure is made accessible to JS code via the DOM
A simple view of this is that the implicit hierarchical (parent>child) relationships of nested elements in the HTML are turned into an explicit hierarchical (tree-like) data structure
So the HTML and DOM are alternative representations of the same thing - 30DOM hierarchyFor the document to be properly represented it also needs
-the entire document including the doctype declaration
- the content of elements (in this case the text in the paragraphs and the link)
--Names and values of all attributes
- style representation - 31DOM nodesEvery item in the DOM hierarchy is said to be a node (A generic object)
Most items are special types of node,
- Indicated by the nodeType property in the node
The key things to remember are
- the entire document is represent by a Document node
- every HTML element is represented by an Element node
- the text inside an element is represented by a Text node(which does not have a corresponding HTML element)
- every HTML attribute is represented by an Attribute node - 32DOM node typesNode is the general type:
- DOM view: HTML document is a tree of Node objects
Nodes have properties and methods
- Properties: nodeType, firstChild, lastChild, parentNode, nextSibling, textContent...
- Methods: appendChild(), hasChildNodes(), hasAttributes(), removeChild().... - 33DOM: node typesELEMENT_NODE
ATTRIBUTE_NODE
TEXT_NODE
CDATA_SECTION_NODE
ENTITY_REFERENCE_NODE
ENTITY_NODE
PROCESSING_INSTRUCTION_NODE
COMMENT_NODE
DOCUMENT_NODE
DOCUMENT_TYPE_NODE
DOCUMENT_FRAGMENT_NODE
NOTATION_NODE - 34Document NodesThe document node represents the entire HTML document. The methods and properties allow us to access and modify element in the document.
Apart from the methods and properties inherited from the node, document has other methods and properties such as
Properties:
- documentElement, title, URL, etc
Methods: write(), getElementById(), getElementByTagName(), createElement(), createTextNode(), createComment() - 35Element NodesElement nodes represent an HTML element. They can have child nodes of type element nodes, text nodes and comment nodes
Properties:
- tagName, id, attribute etc
Methods:
getAttribute(), setAttribute(),...
"Objects that implement the Element interface have all properties
and methods of the Node interface as well as the properties and methods of elements" - 36Attr nodesThe attr node represents an HTML attribute
The attribute property of element returns a NamedNodeMap object which consists of the attribute objects of the element
Nodes in the NamedNodeMap can be accessed by name or by index
Properties:
- Name, value etc
Methods:
- nodemap.setNamedItem(). nodemap.item(), etc - 37Text nodesThe text nodes represent the textual content of an element
Properties:
- isElementContentWhitespace
Methods:
-appendData(), deleteData(), insertData(), etc.. - 38DOM: the data structureSo for any given node we can programmatically identify all of its children(including text nodes) and all of its attributes
In fact we could traverse the entire DOM tree of a document Each node has a property nodeType - 39Navigating the DOM: node to nodeWe need to begin from some point
- Document.documentElement always returns the HTML element of the tree
We can use the following properties to move around in the DOM
- parentNode
-childNodes[nodeNumber]
-firstChild
-lastChild
-nextSibling
previousSibling
Collect all the text in the tags of the document and display it in a popup box
Find out the source of the image in the tag - 40Navigating the DOM: direct accessdocument.getElementById("some_id");
document.getElementsByTagName("div"); - 41DOM manipulationThere are two ways we can change the content of a page element
-the textContent property
document.getElementById("id).textContent="some text"
-the innerHTML property
document.getElementById("id).innerHTML = " some text
" - 42textContent and the DOMtextContent is a property in the node object
Therefore every node in the DOM tree has this property
- This property however makes sense only in the case of HTML elements that have text
- Using this property on other elements will return unexpected results
textContent property sets or gets the text in the child text node of the element
document.getElementById("some_node").textContent = "New Text"; - 43innerHTML and the DOMthe innerHTML property of a node allows us to set the content to an arbitrary string of HTML markup
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- Fichas sobre COMP233, creado por Cherese Eriepa el 29/10/2015.
- Creado por
- Cherese Eriepa
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