1 files changed, 35 insertions, 0 deletions
diff --git a/update.php b/update.php
index ff57c12f3..92b240798 100644
--- a/update.php
+++ b/update.php
@@ -1,5 +1,40 @@
 <?php
 
+/**
+ *
+ * update.php - automatic system update
+ *
+ * Automatically update database schemas and any other development changes such that
+ * copying the latest files from the source code repository will always perform a clean
+ * and painless upgrade.
+ *
+ * Each function in this file is named update_nnnn() where nnnn is an increasing number 
+ * which began counting at 1000.
+ * 
+ * At the top of the file "boot.php" is a define for BUILD_ID. Any time there is a change
+ * to the database schema or one which requires an upgrade path from the existing application,
+ * the BUILD_ID is incremented.
+ *
+ * The current BUILD_ID is stored in the config area of the database. If the application starts up
+ * and BUILD_ID is greater than the last stored build number, we will process every update function 
+ * in order from the currently stored value to the new BUILD_ID. This is expected to bring the system 
+ * up to current without requiring re-installation or manual intervention.
+ *
+ * Once the upgrade functions have completed, the current BUILD_ID is stored as the current value.
+ * The BUILD_ID will always be one greater than the last numbered script in this file. 
+ *
+ * If you change the database schema, the following are required:
+ *    1. Update the file database.sql to match the new schema.
+ *    2. Update this file by adding a new function at the end with the number of the current BUILD_ID.
+ *       This function should modify the current database schema and perform any other steps necessary
+ *       to ensure that upgrade is silent and free from requiring interaction.
+ *    3. Increment the BUILD_ID in boot.php
+ *    4. TEST the upgrade prior to checkin and filing a pull request.
+ *
+ */
+
+
+
 function update_1000() {
 
 	q("ALTER TABLE `item` DROP `like`, DROP `dislike` ");