Index: openacs-4/packages/acs-core-docs/www/tutorial-database.html =================================================================== RCS file: /usr/local/cvsroot/openacs-4/packages/acs-core-docs/www/tutorial-database.html,v diff -u -N -r1.38 -r1.39 --- openacs-4/packages/acs-core-docs/www/tutorial-database.html 7 Jun 2008 20:28:51 -0000 1.38 +++ openacs-4/packages/acs-core-docs/www/tutorial-database.html 12 Jul 2009 01:08:29 -0000 1.39 @@ -1,44 +1,44 @@ - -Setting Up Database Objects

Setting Up Database Objects

by Joel Aufrecht

+ +Setting Up Database Objects

Setting Up Database Objects

by Joel Aufrecht

OpenACS docs are written by the named authors, and may be edited by OpenACS documentation staff. -

Code the data model

We create all database objects with scripts in the - myfirstpackage/sql/ directory. All +

Code the data model

We create all database objects with scripts in the + myfirstpackage/sql/ directory. All database scripts are database-specific and are thus in either - the myfirstpackage/sql/oracle or - myfirstpackage/sql/postgresql directory. + the myfirstpackage/sql/oracle or + myfirstpackage/sql/postgresql directory. Packages can support Oracle, PostgreSQL, or both. In this tutorial, we will be working with PostgreSQL

The first file will be - myfirstpackage-create.sql. The + myfirstpackage-create.sql. The package manager requires a file with the name - packagekey-create.sql, + packagekey-create.sql, which it will run automatically when the package in installed. This file should create all tables and views.

Our package is going to store all of its information in - one table. It takes more than just a CREATE - TABLE command, however, because we want to + one table. It takes more than just a CREATE + TABLE command, however, because we want to integrate our table with the OpenACS system. By making each record in our table an OpenACS object, we gain access to the permissions system and to services that integrate with OpenACS - objects, such as general-comments and - notification. The cost is + objects, such as general-comments and + notification. The cost is that our table creation code must include several functions, stored procedures, and is complicated (even for simple tables).

There are many kinds of OpenACS objects in the system. (You - can see them with the psql code: select object_type from - acs_object_types;.) One such object is the + can see them with the psql code: select object_type from + acs_object_types;.) One such object is the content_item, which is part of the content repository system. To use it, we will make our data objects children of the content_revision object, which is a child of content_item. Not only will we gain the benefits of both OpenACS Objects and content objects, we can also use some content - repository functions to simplify our database creation. (More - information about ACS Objects. More information about the + repository functions to simplify our database creation. (More + information about ACS Objects. More information about the Content Repository.) -

Figure�8.2.�Tutorial Data Model

Tutorial Data Model

The top of each sql file has some +

Figure 9.2. Tutorial Data Model

Tutorial Data Model

The top of each sql file has some standard comments, including doc tags such as - @author which will be picked up + @author which will be picked up by the API browser. The string - $Id$ will automatically be - expanded when the file is checked in to cvs.

[$OPENACS_SERVICE_NAME ~]$ cd /var/lib/aolserver/$OPENACS_SERVICE_NAME/packages/myfirstpackage/sql/postgresql
-[$OPENACS_SERVICE_NAME postgresql]$ emacs myfirstpackage-create.sql

Paste the text below into the file, save, and close.

Figure�8.3.�The Database Creation Script

-- creation script
+      $Id$ will automatically be
+      expanded when the file is checked in to cvs.

[$OPENACS_SERVICE_NAME ~]$ cd /var/lib/aolserver/$OPENACS_SERVICE_NAME/packages/myfirstpackage/sql/postgresql
+[$OPENACS_SERVICE_NAME postgresql]$ emacs myfirstpackage-create.sql

Paste the text below into the file, save, and close.

Figure 9.3. The Database Creation Script

-- creation script
 --
 -- @author joel@aufrecht.org
 -- @cvs-id &Id:$
@@ -56,13 +56,13 @@
 
 -- necessary to work around limitation of content repository:
 select content_folder__register_content_type(-100,'mfp_note','t');
-

The creation script calls a function in PL/pgSQL (PL/pgSQL is a procedural language extention to sql), - content_type__create_type, which +


The creation script calls a function in PL/pgSQL (PL/pgSQL is a procedural language extention to sql), + content_type__create_type, which in turn creates the necessary database changes to support our data - object. Notice the use of "mfp." This is derived from "My - First Package" and ensures that our object is unlikely to conflict + object. Notice the use of "mfp." This is derived from "My + First Package" and ensures that our object is unlikely to conflict with objects from other packages.

Create a database file to drop everything if the package is uninstalled.

-[$OPENACS_SERVICE_NAME postgresql]$ emacs myfirstpackage-drop.sql

Figure�8.4.�Database Deletion Script

-- drop script
+[$OPENACS_SERVICE_NAME postgresql]$ emacs myfirstpackage-drop.sql

Figure 9.4. Database Deletion Script

-- drop script
 --
 -- @author joel@aufrecht.org
 -- @cvs-id &Id:$
@@ -74,19 +74,19 @@
 	   't',
 	   't'
     );
-

(like the creation script the drop script calls a PL/pgSQL function: content_type__drop_type

Run the create script manually to add your tables and functions.

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-create.sql
+

(like the creation script the drop script calls a PL/pgSQL function: content_type__drop_type

Run the create script manually to add your tables and functions.

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-create.sql
 psql:myfirstpackage-create.sql:15: NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index 'mfp_notes_pkey' for table 'mfp_notes'
 psql:myfirstpackage-create.sql:15: NOTICE:  CREATE TABLE will create implicit trigger(s) for FOREIGN KEY check(s)
  content_type__create_type
 ---------------------------
                          0
 (1 row)
 
-[$OPENACS_SERVICE_NAME postgresql]$

If there are errors, use them to debug the sql file and try again. If there are errors in the database table creation, you may need to run the drop script to drop the table so that you can recreate it. The drop script will probably have errors since some of the things it's trying to drop may be missing. They can be ignored.

Once you get the same output as shown above, test the drop script:

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-drop.sql
+[$OPENACS_SERVICE_NAME postgresql]$

If there are errors, use them to debug the sql file and try again. If there are errors in the database table creation, you may need to run the drop script to drop the table so that you can recreate it. The drop script will probably have errors since some of the things it's trying to drop may be missing. They can be ignored.

Once you get the same output as shown above, test the drop script:

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-drop.sql
 
  content_type__drop_type
 -------------------------
                        0
 (1 row)
 
-[$OPENACS_SERVICE_NAME postgresql]$

Once both scripts are working without errors, run the create script one last time and proceed.

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-create.sql
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+[$OPENACS_SERVICE_NAME postgresql]$

Once both scripts are working without errors, run the create script one last time and proceed.

[$OPENACS_SERVICE_NAME postgresql]$ psql service0 -f myfirstpackage-create.sql
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