This might be helpful. If you want to specifically see the methods for the various models or whatever, rather than a general understanding of "why", you could use this bit of code to show all the methods of a Model (or whatever)
<?php
define('MAGENTO_ROOT', getcwd());
define("DIRECT_OUTPUT",true);
define("ADMIN_STORE_ID",1);
include_once("app/Mage.php");
Mage::app();
Mage::setIsDeveloperMode(true);
$myCategory = Mage::getModel("catalog/category")->load(11); //id would be some valid category id
$className = get_class($myCategory); //this will get the actual class name - easier that looking it up yourself :)
echo "<h1>".$className." Methods</h1>";
echo "<ul>";
foreach(get_class_methods($myCategory ) as $method){
$r = new ReflectionMethod($className,$method);
$params = $r->getParameters();
echo "<li>";
echo $method."(";
$count=0;
foreach($params as $param){
$count++;
if($count>1){
echo ",";
}
echo $param->getName();
}
echo ")</li>";
}
echo "</ul>";
?>
In this example you would get something like this:
Mage_Catalog_Model_Category Methods
getUrlInstance()
getUrlRewrite()
getTreeModel()
getTreeModelInstance()
move(parentId,afterCategoryId)
getDefaultAttributeSetId()
getProductCollection()
getAttributes(noDesignAttributes)
getProductsPosition()
getStoreIds()
getLayoutUpdateHandle()
getStoreId()
setStoreId(storeId)
getUrl()
getUrlModel()
getCategoryIdUrl()
formatUrlKey(str)
getImageUrl()
getUrlPath()
getParentCategory()
getParentId()
getParentIds()
getCustomDesignDate()
getDesignAttributes()
getAllChildren(asArray)
getChildren()
getPathInStore()
checkId(id)
getPathIds()
getLevel()
verifyIds(ids)
hasChildren()
getRequestPath()
getName()
getAnchorsAbove()
getProductCount()
getCategories(parent,recursionLevel,sorted,asCollection,toLoad)
getParentCategories()
getChildrenCategories()
getChildrenCategoriesWithInactive()
getParentDesignCategory()
isInRootCategoryList()
getAvailableSortBy()
getAvailableSortByOptions()
getDefaultSortBy()
validate()
afterCommitCallback()
lockAttribute(attributeCode)
unlockAttribute(attributeCode)
unlockAttributes()
getLockedAttributes()
hasLockedAttributes()
isLockedAttribute(attributeCode)
setData(key,value)
unsetData(key)
getResourceCollection()
loadByAttribute(attribute,value,additionalAttributes)
getStore()
getWebsiteStoreIds()
setAttributeDefaultValue(attributeCode,value)
getAttributeDefaultValue(attributeCode)
setExistsStoreValueFlag(attributeCode)
getExistsStoreValueFlag(attributeCode)
isDeleteable()
setIsDeleteable(value)
isReadonly()
setIsReadonly(value)
getIdFieldName()
getId()
setId(id)
getResourceName()
getCollection()
load(id,field)
afterLoad()
save()
isObjectNew(flag)
getCacheTags()
getCacheIdTags()
cleanModelCache()
delete()
getResource()
getEntityId()
clearInstance()
__construct()
_addFullNames()
_initOldFieldsMap()
_prepareSyncFieldsMap()
isDeleted(isDeleted)
hasDataChanges()
setIdFieldName(name)
addData(arr)
unsetOldData(key)
getData(key,index)
_getData(key)
setDataUsingMethod(key,args)
getDataUsingMethod(key,args)
getDataSetDefault(key,default)
hasData(key)
__toArray(arrAttributes)
toArray(arrAttributes)
_prepareArray(arr,elements)
__toXml(arrAttributes,rootName,addOpenTag,addCdata)
toXml(arrAttributes,rootName,addOpenTag,addCdata)
__toJson(arrAttributes)
toJson(arrAttributes)
toString(format)
__call(method,args)
__get(var)
__set(var,value)
isEmpty()
_underscore(name)
_camelize(name)
serialize(attributes,valueSeparator,fieldSeparator,quote)
getOrigData(key)
setOrigData(key,data)
dataHasChangedFor(field)
setDataChanges(value)
debug(data,objects)
offsetSet(offset,value)
offsetExists(offset)
offsetUnset(offset)
offsetGet(offset)
isDirty(field)
flagDirty(field,flag)