CODING.md: updates

CODING.md

+Notes / Best Practices for Coding
+=================================
+
+General
+=======
+
+* When qfq starts, it looks for the formname at: 
+  1. Typo3 Bodytext Element,
+  2. For the 'SIP' ($_GET['s'])
+  3. $_GET variables 'form' and 'r' (=recordId)
+
+* The active formname is stored in   $this->store->setVar(SYSTEM_FORM, $formName, STORE_SYSTEM);
+
+* In QuickFormQuery.php the whole Form will be copied to $this->formSpec and depending on further processing, the elements are
+available in $this->feNative and $this->feAction.
+  * The Form specificaton (table form) will be evaluated after loading.
+  * The FormElement specification will be evaluated later on in BuildForm*.php
+
+* Get the recent SIP, Formname, RecordId with:
+
+[src] $this->store->getVar('form', STORE_SIP), or
+[src] $this->store->getStore(STORE_SIP)
+
+  * Check Contstants.php for known Store members
+
+Debug / Log / Errormessages
+===========================
+
+
+* Before firing a SQL or doing processing of an FormElement, set some debugging / error variables:
+
+[src] $this->store->setVar(SYSTEM_SQL_RAW, STORE_SYSTEM)
+
+* Available fields:
+<code>
+SYSTEM_SQL_RAW
+SYSTEM_SQL_FINAL
+SYSTEM_SQL_COUNT
+SYSTEM_SQL_PARAM_ARRAY
+SYSTEM_FORM = CLIENT_FORM;                        // '<formName> / <formId>'
+SYSTEM_FORM_ELEMENT = 'formElement';              // '<formElementName> / <formElementeId>'
+SYSTEM_FORM_ELEMENT_COLUMN = 'formElementColumn'; // '<columnname of current processed formElement>'
+</code>
+
+Stores
+======
+
+* Get submitted POST variables by
+
+[src] $values = $this->store->getStore(STORE_CLIENT)
+
+
+
+Primary Table
+=============
+* For the primary table all informations are available in STORE_TABLE_DEFAULT and STORE_TABLE_COLUMN_TYPES.
+* Get all columns of the primary table by
+
+[src] array_keys($this->getStore(STORE_TABLE_COLUMN_TYPES))
+
+* Get the recent record in STORE_RECORD and the parent record (multiforms) in STORE_PARENT_RECORD.
+