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Database connectivity
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Fetch from database
If we wish to get something from the database we usually use a template function called fetch. fetch takes three arguments: name of the module we fetch from, what we wish to fetch (the fetch function) and, optionally, a set of parameters.
The set of parameters are sent as an associative array. Associative arrays are created with the hash function.
Example:
hash( 'First name', 'Jo Henrik', 'Last name', 'Endrerud' )
This would create an array with two values. The first key is First name with the value Jo Henrik, the second key is Last name with value Endrerud.
It doesn't matter if you use single or double quotes, but it is a good practise to use double in your HTML and single in your eZ publish code.
We usually wish to fetch information on the content of the nodes. The only module we will explain here is therefore the content module.
Fetch one node
To fetch one node we use the fetch function node. This function take one parameter, node_id, that defines the ID of the node we wish to fetch.
Example:
{let mynode=fetch( 'content', 'node', hash( 'node_id', 5 ) )}
This would fetch the node with ID 5 from the database and store it in the variable mynode. We can then access the $mynode object and get the information we want (for example content from the data map).
Fetch many objects
If we wish to make a list of all nodes placed under another node (i.e. a folder) in the tree, we use a fetch function called list. This function takes many parameters, most of them are optional. The one required parameter is called parent_node_id and it describes what parent we should fetch the nodes from.
Example:
{let elements=fetch( 'content', 'list', hash( 'parent_node_id', 2 ) )}
Our variable elements will here be an array containing all nodes placed under node 2. list have several other parameters to customize the way the nodes are returned.
|
Parameter |
Description |
|---|---|
|
parent_node_id |
Parent placement of the nodes we wish to fetch |
|
sort_by |
How we should sort the nodes |
|
limit |
How many nodes we maximum should fetch |
|
offset |
The position we should start the node if we don't want every node |
|
class_filter_array |
An array of classes if we only wish to include some classes |
|
class_filter_type |
Type of filtering, could be include or exclude. Either only use the classes declared in class_filter_array or include every class except the ones declared |
More fetch functions
eZ systems has made several more fetch functions for you. This is functions for counting number of nodes under another node, fetching an entire tree from a specific node and so on. You can check the file kernel/content/function_definition.php for more information about the functions and parameters you can use.
Comments
FYI: Grammatical Correction
James Ashley
Tuesday 09 August 2005 5:22:33 am
[quote]This is functions for counting number of nodes under another node, fetching an entire tree from a specific node and so on[/quote]
It would be closer to "proper" English to say:
There are functions for: 1) counting the number of nodes under another node, 2) fetching an entire tree from a specific node, 3) and so on.
Well, that's not really *that* much more grammatically correct. But it probably looks more correct to a Native English speaker. A "grammatical" version might look like:
There are functions for both counting the number of nodes under another node and fetching an entire tree from a specific node, among others.
I'm not sure how readable the "grammatically correct" version is, though. English is *such* an annoying language. (I say this with authority, since I'm a native speaker).