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Changing to code-block

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WireShout
2012-12-13 15:20:40 -05:00
parent 140f2bedc3
commit cac15ff662
1 changed files with 61 additions and 55 deletions
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116
developer_manual/data-migration.rst
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@@ -13,30 +13,34 @@ Database Data
To make exporting database data really easy, the class OC_Migration_Content has a method called copyRows() which will save these rows for you given some options. Take a look at the export function for the bookmarks app:
``function export( ){
OC_Log::write('migration','starting export for bookmarks',OC_Log::INFO);
$options = array(
'table'=>'bookmarks',
'matchcol'=>'user_id',
'matchval'=>$this->uid,
'idcol'=>'id'
);
$ids = $this->content->copyRows( $options );
$options = array(
'table'=>'bookmarks_tags',
'matchcol'=>'bookmark_id',
'matchval'=>$ids
);
// Export tags
$ids2 = $this->content->copyRows( $options );
// If both returned some ids then they worked
if( is_array( $ids ) && is_array( $ids2 ) )
{
return true;
} else {
return false;
}
}``
.. code-block:: php
function export( ){
OC_Log::write('migration','starting export for bookmarks',OC_Log::INFO);
$options = array(
'table'=>'bookmarks',
'matchcol'=>'user_id',
'matchval'=>$this->uid,
'idcol'=>'id'
);
$ids = $this->content->copyRows( $options );
$options = array(
'table'=>'bookmarks_tags',
'matchcol'=>'bookmark_id',
'matchval'=>$ids
);
// Export tags
$ids2 = $this->content->copyRows( $options );
// If both returned some ids then they worked
if( is_array( $ids ) && is_array( $ids2 ) )
{
return true;
} else {
return false;
}
}
The bookmarks app stores all of its data in the database, in two tables: *PREFIX*bookmarks and *PREFIX*bookmarks_tags so to export this, we need to run copyRows() twice. Here is an explanation of the options passed to OC_Migration_Content::copyRows():
@@ -57,36 +61,38 @@ Import
Import is a little more tricky as we have to take into account data from different versions of your app, and also handle changing primary keys. Here is the import function for the bookmarks app which imports bookmarks and tags:
``function import(){
switch( $this->appinfo->version ){
default:
// All versions of the app have had the same db structure
// so all can use the same import function
$query = $this->content->prepare( "SELECT * FROM bookmarks WHERE user_id LIKE ?" );
$results = $query->execute( array( $this->olduid ) );
$idmap = array();
while( $row = $results->fetchRow() ){
// Import each bookmark, saving its id into the map
$query = OC_DB::prepare( "INSERT INTO *PREFIX*bookmarks(url, title, user_id, public, added, lastmodified) VALUES (?, ?, ?, ?, ?, ?)" );
$query->execute( array( $row['url'], $row['title'], $this->uid, $row['public'], $row['added'], $row['lastmodified'] ) );
// Map the id
$idmap[$row['id']] = OC_DB::insertid();
}
// Now tags
foreach($idmap as $oldid => $newid){
$query = $this->content->prepare( "SELECT * FROM bookmarks_tags WHERE user_id LIKE ?" );
$results = $query->execute( array( $oldid ) );
while( $row = $data->fetchRow() ){
// Import the tags for this bookmark, using the new bookmark id
$query = OC_DB::prepare( "INSERT INTO *PREFIX*bookmarks_tags(bookmark_id, tag) VALUES (?, ?)" );
$query->execute( array( $newid, $row['tag'] ) );
}
}
// All done!
break;
}
return true;
}``
.. code-block:: php
function import(){
switch( $this->appinfo->version ){
default:
// All versions of the app have had the same db structure
// so all can use the same import function
$query = $this->content->prepare( "SELECT * FROM bookmarks WHERE user_id LIKE ?" );
$results = $query->execute( array( $this->olduid ) );
$idmap = array();
while( $row = $results->fetchRow() ){
// Import each bookmark, saving its id into the map
$query = OC_DB::prepare( "INSERT INTO *PREFIX*bookmarks(url, title, user_id, public, added, lastmodified) VALUES (?, ?, ?, ?, ?, ?)" );
$query->execute( array( $row['url'], $row['title'], $this->uid, $row['public'], $row['added'], $row['lastmodified'] ) );
// Map the id
$idmap[$row['id']] = OC_DB::insertid();
}
// Now tags
foreach($idmap as $oldid => $newid){
$query = $this->content->prepare( "SELECT * FROM bookmarks_tags WHERE user_id LIKE ?" );
$results = $query->execute( array( $oldid ) );
while( $row = $data->fetchRow() ){
// Import the tags for this bookmark, using the new bookmark id
$query = OC_DB::prepare( "INSERT INTO *PREFIX*bookmarks_tags(bookmark_id, tag) VALUES (?, ?)" );
$query->execute( array( $newid, $row['tag'] ) );
}
}
// All done!
break;
}
return true;
}
We start off by using a switch to run different import code for different versions of your app. $this->appinfo->version contains the version string from the info.xml of your app. In the case of the bookmarks app the db structure has not changed, so only one version of import code is needed.To import the db data, first we must retrive it from the migration.db. To do this we use the prepare method from OC_Migration_Content, which returns a MDB2 db object. We then cycle through the bookmarks in migration.db and insert them into the owncloud database. The important bit is the ‘idmapping’. After inserting a boookmark, The new id of the bookmark is saved in an array, with the key being the old id of the bookmark. This means when inserting the tags, we know what the new id of the bookmark is simply by getting the value of $idmap['oldid']. Remember this part of the import code may be a good place to emit some hooks depending on your app. For example the contacts app could emit some hooks to show some contacts have been added.After importing the bookmarks, we must import the tags. It is a very similar process to importing the bookmarks, except we have to take into account the changes in primary keys. This is done by using a foreach key in the $idmap array, and then inserting the tags using the new id.After all this, we must return a boolean value to indicate the success or failure of the import.Again, app data files stored in data/userid/appname will be automatically copied over before the apps import function is executed, this allows you to manipulate the imported files if necessary.
@@ -101,4 +107,4 @@ You can view other migration providers here:
* `Contact migration provider`_
.. _Bookmarks migration provider: http://gitorious.org/owncloud/owncloud/blobs/migration/apps/bookmarks/appinfo/migrate.php
.. _Contact migration provider: http://gitorious.org/owncloud/owncloud/blobs/migration/apps/contacts/appinfo/migrate.php
.. _Contact migration provider: http://gitorious.org/owncloud/owncloud/blobs/migration/apps/contacts/appinfo/migrate.php