Task Title Description Task Number
For our simple example:
Title - want versions Description - want versions Task Number - do NOT want versions
Versioned portion:
create table pm_tasks_revisions (
task_revision_id
integer
constraint pm_tasks_revisions_id_pk
primary key
constraint pm_tasks_revisions_id_fk
references cr_revisions(revision_id)
on delete cascade,
title
varchar(100),
description
varchar(4000)
);
create table pm_tasks (
task_id
integer
constraint pm_tasks_id_pk
primary key
constraint pm_tasks_id_fk
references cr_items(item_id)
on delete cascade,
task_number
integer
)
cr_items and cr_revisions tables. For example, you can't call you key on the pm_tasks_revisions table revision_id. Why? There are some views that are automatically generated that combine these tables for you, but they won't be created if the names conflict. I'll describe what these views are later, but they are useful. You were warned.
Notice that each table uses as its primary key a reference to either the cr_revisions table or the cr_items table. A content item is basically just some content: either text or binary data. The contents revisions table keeps track of which version from the tasks_revisions table is the most current, and which one is live.
All this is going inside the sql/postgresql/project-manager-create.sql file. Your name will be different of course.
I thus need to to
--create the content type
select content_type__create_type (
'pm_task', -- content_type
'content_revision', -- not sure what this is
'Task', -- pretty_name
'Tasks', -- pretty_plural
'pm_tasks_revisions', -- table name
'task_id', -- id_column
'content_revision.revision_name'
);
-- add in attributes
select content_type__create_attribute (
'pm_task', -- content_type
'start_date', -- attribute_name
'date', -- datatype (string, number, boolean, date, keyword, integer)
'Start date', -- pretty_name
'Start dates', -- pretty_plural
null, -- sort_order
null, -- default value
'timestamptz' -- column_spec
);
select content_type__create_attribute (
'pm_task', -- content_type
'end_date', -- attribute_name
'date', -- datatype
'End date', -- pretty_name
'End dates', -- pretty_plural
null, -- sort_order
null, -- default value
'timestamptz' -- column_spec
);
select content_type__create_attribute (
'pm_task', -- content_type
'percent_complete', -- attribute_name
'number', -- datatype
'Percent complete', -- pretty_name
'Percents complete', -- pretty_plural
null, -- sort_order
null, -- default value
'numeric' -- column_spec
);
Side effect: once you've created the content type, the content repository creates a view for you called pm_tasks_revisionsx. Note the x at the end of the name. If you're using Postgres, I believe it will also create a view for you called pm_tasks_revisionsi
Why are these two views created? the x view is created for selection, and the i view is created for inserts. They join the acs_objects, cr_revisions, and our pm_tasks_revisions tables together. Try viewing them to get an idea of how they might be useful.
create table or alter table add column statements in SQL, but this also adds in some meta-data that will be useful to you. The disadvantage is that you have to call the content repository API. The advantage is that someday you'll be able to do really cool stuff with it, like automatically generate interfaces that take advantage of the new columns and tables you've added. Another nice thing is that all that messy business of defining your attributes through the API is taken care of.
Types is the content repository are another term for tables, although that doesn't explain it completely. Types are also kept track of within OpenACS, in the acs_object_types table, so the system knows about the tables you create, and can do some intelligent things with them.
A lot of the intelligent things you can do with this information is still being built. But imagine for example that you are using the project manager package I've written. You work at an ice cream company, and every task that is done also has an associated ice cream flavor with it (yeah, this isn't a good example, but pay attention anyway). If I've written the project manager to take advantage of it, when you add in this extra attribute to the pm_tasks_revisions table, the UI aspects will be automatically taken care of. You'll be able to select a flavor when you edit a task, and it will be shown on the task view page. This is the direction OpenACS development is going, and it will be really really cool!
First, I'm going to describe how to extend other content repository tables using the CR API. Then, I'll describe how to set up your own tables as well:
As you recall from earlier in this page, attributes are just another term for columns in a table. The Content Repository has a mechanism for adding and removing columns via the pl/sql API. If you check your /api-doc: /api-doc/plsql-subprogram-one?type=FUNCTION&name=content%5ftype%5f%5fcreate%5fattribute
, you'll see that there is a way to extend the columns programmatically.
Why would you want to do this? For project manager, I decided to do this because I wanted to customize my local version of the projects table, to account for company-specific information. That way, I can have a separate edit page for those types, but not have a separate table to join against.
Instead of doing this:
alter table pm_projects add column
target_date date;
select content_type__create_attribute(
'pm_project',
'target_date',
'date',
'Target date',
'Target dates',
null,
null,
'date'
);
select content_type__create_attribute(
'pm_project',
'company_id',
'integer',
'Company',
'Companies',
null,
null,
'integer constraint pm_project_comp_fk references organizations'
);pm_task__new_task_item function (which we'll write in a little bit). This function creates both a new content item, and a new content revision. Information is actually stored in four tables, believe it or not: cr_revisions, cr_items, pm_tasks, and pm_tasks_revisions.
The task number is stored in pm_tasks, the title and description are stored in pm_tasks_revisions, and some additional information like who entered the information is stored in cr_revisions and cr_items.
Whenever you make a change to this item, you don't change the table yourself, but add a revision, using your pm_task__new_task_revision function (which we'll write in a little bit). This function adds another revision, but not another item or cr_item. After you've added another revision, you'll have two revisions and one item. Two entries in cr_revisions (and pm_tasks_revisions), and one item in cr_items and pm_tasks.
The cr_revisions table keeps track of which item is the most recent, and which item is "live". For the edit-this-page application, for example, this is used to keep track of which revision to a page is actually being served to users.
In your code, you'll use your pm_tasks_revisionsx view, which joins the pm_tasks_revisions table with the cr_revisions table (and it might even join in cr_items -- I forget at the moment).
select define_function_args('pm_task__new_task_item', 'task_id, project_id, title, description, end_date, percent_complete, estimated_hours_work, estimated_hours_work_min, estimated_hours_work_max, creation_date, creation_user, creation_ip, package_id');
create function pm_task__new_task_item (
integer, -- task_id
integer, -- project_id
varchar, -- title
varchar, -- description
timestamptz, -- end_date
numeric, -- percent_complete
numeric, -- estimated_hours_work
numeric, -- estimated_hours_work_min
numeric, -- estimated_hours_work_max,
timestamptz, -- creation_date
integer, -- creation_user
varchar, -- creation_ip
integer -- package_id
) returns integer
as '
declare
p_task_id alias for $1;
p_project_id alias for $2;
p_title alias for $3;
p_description alias for $4;
p_end_date alias for $5;
p_percent_complete alias for $6;
p_estimated_hours_work alias for $7;
p_estimated_hours_work_min alias for $8;
p_estimated_hours_work_max alias for $9;
p_creation_date alias for $10;
p_creation_user alias for $11;
p_creation_ip alias for $12;
p_package_id alias for $13;
v_item_id cr_items.item_id%TYPE;
v_revision_id cr_revisions.revision_id%TYPE;
v_id cr_items.item_id%TYPE;
v_task_number integer;
begin
select acs_object_id_seq.nextval into v_id from dual;
-- We want to put the task under the project item
-- create the task_number
v_item_id := content_item__new (
v_id::varchar, -- name
p_project_id, -- parent_id
v_id, -- item_id
null, -- locale
now(), -- creation_date
p_creation_user, -- creation_user
p_package_id, -- context_id
p_creation_ip, -- creation_ip
''content_item'', -- item_subtype
''pm_task'', -- content_type
p_title, -- title
p_description, -- description
''text/plain'', -- mime_type
null, -- nls_language
null -- data
);
v_revision_id := content_revision__new (
p_title, -- title
p_description, -- description
now(), -- publish_date
''text/plain'', -- mime_type
NULL, -- nls_language
NULL, -- data
v_item_id, -- item_id
NULL, -- revision_id
now(), -- creation_date
p_creation_user, -- creation_user
p_creation_ip -- creation_ip
);
PERFORM content_item__set_live_revision (v_revision_id);
insert into pm_tasks (
task_id, task_number)
values (
v_item_id, v_task_number);
insert into pm_tasks_revisions (
task_revision_id, end_date, percent_complete, estimated_hours_work, estimated_hours_work_min, estimated_hours_work_max, actual_hours_worked)
values (
v_revision_id, p_end_date, p_percent_complete, p_estimated_hours_work, p_estimated_hours_work_min, p_estimated_hours_work_max, ''0'');
PERFORM acs_permission__grant_permission(
v_revision_id,
p_creation_user,
''admin''
);
return v_revision_id;
end;' language 'plpgsql';
select define_function_args('pm_task__new_task_revision', 'task_id, project_id, title, description, end_date, percent_complete, estimated_hours_work, estimated_hours_work_min, estimated_hours_work_max, actual_hours_worked, creation_date, creation_user, creation_ip, package_id');
create function pm_task__new_task_revision (
integer, -- task_id (the item_id)
integer, -- project_id
varchar, -- title
varchar, -- description
timestamptz, -- end_date
numeric, -- percent_complete
numeric, -- estimated_hours_work
numeric, -- estimated_hours_work_min
numeric, -- estimated_hours_work_max
numeric, -- actual_hours_worked
timestamptz, -- creation_date
integer, -- creation_user
varchar, -- creation_ip
integer -- package_id
) returns integer
as '
declare
p_task_id alias for $1;
p_project_id alias for $2;
p_title alias for $3;
p_description alias for $4;
p_end_date alias for $5;
p_percent_complete alias for $6;
p_estimated_hours_work alias for $7;
p_estimated_hours_work_min alias for $8;
p_estimated_hours_work_max alias for $9;
p_actual_hours_worked alias for $10;
p_creation_date alias for $11;
p_creation_user alias for $12;
p_creation_ip alias for $13;
p_package_id alias for $14;
v_revision_id cr_revisions.revision_id%TYPE;
v_id cr_items.item_id%TYPE;
begin
select acs_object_id_seq.nextval into v_id from dual;
-- We want to put the task under the project item
v_revision_id := content_revision__new (
p_title, -- title
p_description, -- description
now(), -- publish_date
''text/plain'', -- mime_type
NULL, -- nls_language
NULL, -- data
p_task_id, -- item_id
NULL, -- revision_id
now(), -- creation_date
p_creation_user, -- creation_user
p_creation_ip -- creation_ip
);
PERFORM content_item__set_live_revision (v_revision_id);
insert into pm_tasks_revisions (
task_revision_id, end_date, percent_complete, estimated_hours_work, estimated_hours_work_min, estimated_hours_work_max, actual_hours_worked)
values (
v_revision_id, p_end_date, p_percent_complete, p_estimated_hours_work, p_estimated_hours_work_min, p_estimated_hours_work_max, p_actual_hours_worked);
PERFORM acs_permission__grant_permission(
v_revision_id,
p_creation_user,
''admin''
);
return v_revision_id;
end;' language 'plpgsql';
-- The delete function deletes a record and all related overhead.
select define_function_args('pm_task__delete_task_item', 'task_id');
create or replace function pm_task__delete_task_item (integer)
returns integer as '
declare
p_task_id alias for $1;
begin
delete from pm_tasks_revisions
where task_revision_id in (select revision_id from pm_tasks_revisionsx where item_id = p_task_id);
delete from pm_tasks
where task_id = p_task_id;
raise NOTICE ''Deleting pm_task...'';
PERFORM content_item__delete(p_task_id);
return 0;
end;' language 'plpgsql';
item_id - unique id for this item, will be different than the revision_idcr_revisions:
parent_id - used to group items into a hierarchy (see below)
name - this is used to make a URL by the content repository. It must be unique per content folder. You can use a number, or something like project_231. One way to do this is to set it equal to a title plus the item_id.
locale - not sure, probably for internationalization support
live_revision - this is equal to the cr_revision table's revision_id that is the live version
latest_revision - this is equal to the cr_revision table's revision_id that is the latest version
publish_status - not sure
content_type - not sure
storage_type - not sure, probably text or binary?
storage_area_key - not sure
tree_sortkey - a utility column used in hierarchical queries.
revision_id - a unique id for this revision.
item_id - a reference to the item_id for this revision
title - you can use this for your application. For example, My Big Project
description - you can use this for your application, as a longer description.
publish_date - the date this was published. Not sure if this is for your use, or internal
mime_type - the mime type.
nls_language - I believe this is for internationalization
lob - the binary content.
content - the text content.
content_length - the length of the text or binary content?
Using this structure is optional, but useful in many circumstances.
The facility for this is built into the cr_items data model. This makes sense, because you wouldn't want your hierarchy associated with each revision. Here's how Postgres describes the cr_items table:
Table "public.cr_items"
Column | Type | Modifiers
------------------+------------------------+-----------------------------
item_id | integer | not null
parent_id | integer | not null
name | character varying(400) | not null
locale | character varying(4) |
live_revision | integer |
latest_revision | integer |
publish_status | character varying(40) |
content_type | character varying(100) |
storage_type | character varying(10) | not null default 'text'
storage_area_key | character varying(100) | not null default 'CR_FILES'
tree_sortkey | bit varying |
parent_id refers to either a content item (cr_items), or a subclass of a content_item (such as cr_folders). I'll explain more later about cr_folders.
One thing that you might want to do for your application is to give the application its own root directory. Because the content repository is shared among applications, this separates it off from other applications. They can still use the items in your application, but it must be a more deliberate process. If you don't create your own root directory, you may see strange-looking data from other applications in your application, or see your application's data in other applications. There are times when you'll want to do this, but probably not until you're much more familiar with the content repository. Another reason for creating your own root repository is that you application may be mounted several times. If you want to separate the directory structure between instances of your application, you need to create your own root directory:
-- Creates and returns a unique name for new project folders
select define_function_args('pm_project__new_unique_name', 'package_id');
create function pm_project__new_unique_name (integer)
returns text as '
declare
p_package_id alias for $1;
v_name cr_items.name%TYPE;
v_package_key apm_packages.package_key%TYPE;
v_id integer;
begin
select package_key into v_package_key from apm_packages
where package_id = p_package_id;
select acs_object_id_seq.nextval into v_id from dual;
-- Set the name
select v_package_key || ''_'' ||
to_char(current_timestamp, ''YYYYMMDD'') || ''_'' ||
v_id into v_name;
return v_name;
end;' language 'plpgsql';
select define_function_args('pm_project__new_root_folder', 'package_id');
create function pm_project__new_root_folder (integer)
returns integer as '
declare
p_package_id alias for $1;
v_folder_id cr_folders.folder_id%TYPE;
v_folder_name cr_items.name%TYPE;
begin
-- Set the folder name
v_folder_name := pm_project__new_unique_name (p_package_id);
v_folder_id := content_folder__new (
v_folder_name, -- name
''Projects'', -- label
''Project Repository'', -- description
p_package_id -- parent_id
);
-- Register the standard content types
PERFORM content_folder__register_content_type (
v_folder_id, -- folder_id
''pm_project'', -- content_type
''f'' -- include_subtypes
);
-- TODO: Handle Permissions here for this folder.
return v_folder_id;
end;' language 'plpgsql';
Typically, this definition would go in your sql/postgresql/project-manager-create.sql file. If this file is broken in several parts, this would go in the project-manager-create-functions.sql portion.
Once you've created your root directory, you will set the parent_id of your items to the id for the new root repository (in our case, it's returned from the pm_project__new_root_folder function)
In the project-manager application, we'll create a root repository, and make all projects under that root repository. That means they'll all have a parent_id set to the root repository. However, we also want to make projects that are sub-projects of other projects. In that case, we will set the parent_id of the sub-project to the item_id of the parent.
cr_items, and the only real difference is that they contain no data, except for a label and description.
If you create folders for your application, then you'll need to make sure you manage them along with your other objects. For example, if you were to add a folder for each of your objects, then you would probably want to make sure you delete the folder when you delete the object.
However, in many cases you are not creating more than one folder. In fact, the only folder you might have will be the root folder you create for each instance of your application (if you install the project-manager in two parts of your web server, for example, it should have two different root folders). When your application is running, it can determine the root folder by searching the cr_folders table. Here's the definition of that table:
Table "public.cr_folders"
Column | Type | Modifiers
--------------------+-------------------------+-------------
folder_id | integer | not null
label | character varying(1000) |
description | text |
has_child_folders | boolean | default 'f'
has_child_symlinks | boolean | default 'f'
package_id | integer |
package_id column. The nice thing about this column is that you can use it to find the root repository, if you only have one folder per instance of your application. You can get your package_id using this call within your .tcl file:
Then you can find the root repository by using a query like this:set package_id [ad_conn package_id]
select folder_id from cr_folders where package_id = :package_id;
| Get latest revision (Tcl) | set live_revision_id [db_exec_plsql get_live_revision "select content_item__get_live_revision(:item_id)"] |
|---|---|
| Get latest revision (pl/sql) | live_revision_id := content_item__get_live_revision(:item_id); |
The item_id identifies the content item with which the revision is associated.
Likewise, the most recent revision of a content item can be obtained with the content_item__get_latest_revision function
cr_revisions table, and a table that you set up to store specialized data. In this case, the title (I think), byline, and publication date would be stored in a specialized table.The problem seems to be that there were still items in theReferential Integrity: attempting to delete live_revision: 658
cr_items table. You can remove them using select content_item__delete(648); in psql. You get the codes by doing a query like this:
Really, however, what you need to do is make sure your __delete and drop scripts first go through and delete all children of those items. I'm not sure if you need to delete the items themselves -- I believe they may be dropped by themselves when the tables are dropped, because of theselect i.item_id, r.revision_id, r.title, i.content_type from cr_items i, cr_revisions r where i.item_id = r.item_id order by i.item_id, r.revision_id;
cascade portion of the SQL data model.
When I was troubleshooting folders, I found this query useful:
select f.folder_id,f.label,f.description,i.content_type from cr_folders f, cr_items i where f.folder_id = i.item_id;
Once again, thanks to daveb for help in tracking this down (he rocks!).