This is an old revision of the document!
User database revised
Contains suggested changes to the User database design and API that are needed for subscription information and possibly other needs. Changes to the original User database description are rendered in bold.
Design
Database tables
UserTable
| U_id | A_id | U_name | U_email | U_password | U_institution | U_telephone | U_session |
DataSet
| DS_id | U_id | A_id | DS_name |
Info
| I_id | U_id | DS_id | I_type | I_content |
File
| DS_id | F_name | F_timestamp | F_size | F_status | F_errurl |
The table details are presented below:
UserTable
| U_id | Unique user id (autoincremented number). Primary key |
|---|---|
| A_id | Application id. Many METAMOD applications share the same database. This field has the same value as the APPLICATION_ID in the master_config.txt file. |
| U_name | User name as given in registration form |
| U_email | User E-mail address as given in registration form |
| U_password | User password |
| U_institution | User institution acronym as given in registration form |
| U_telephone | User telephone number as given in registration form |
| U_session | User session id. Random string generated when the user initiate a new interactive session. |
The U_session field is used to track the state of an interactive user session. The user may only have one interactive session active at any time. If the user initiate a new session when another session is already active, the old session disappears. If the user tries to continue the old session, an error message will be submitted. This is the same mechanism used in the old (METAMOD 2.3 and earlier) file-based version.
The A_id field connects the user to one of the METAMOD applications that share the same database. If the same person wants to be a user of more than one of these METAMOD applications, she/he must apply for a user account in each application, and the database will contain independent rows in the user table, one for each application.
DataSet
| DS_id | Unique dataset id (autoincremented number). Primary key. Not same number as in the Metadata Database |
|---|---|
| U_id | Identifies the user owning the dataset. |
| A_id | Application id. |
| DS_name | Dataset name. Name of dataset as provided by the user. Not the same name as in the corresponding field in the Metadata Database. But the last part of the name found in the Metadata Database field (everything after '/') will correspond to this field. |
The combination of the A_id and DS_name fields will provide an alternative unique key that can be used to find a dataset without knowing the owning user.
Info
This table is used to contain various information connected to a dataset and/or a user. Each row has a serial unique identifier (I_id). The row can be connected to a dataset through the DS_id foreign key, and to a user through the U_id foreign key. Note that all Info-rows connected to a dataset is also indirectly connected to the owner of the dataset. This is not explicitly expressed in this table. In cases where values for both U_id and DS_id exist, the U_id will usually point to a user that do not own the dataset.
A type tag (I_type) field tells what kind of information is contained in the row. The value is a short acronym for a limited set of information types. The piece of information is found in the I_content text field.
| I_id | Unique id (autoincremented number). Primary key |
|---|---|
| U_id | Identifiles a user this info-row is connected to. Will be missing (NULL) if the information is not connected to a user |
| DS_id | Identifiles a dataset this info-row is connected to. Will be missing (NULL) if the information is not connected to a dataset |
| I_type | Type tag. Short acronym that identifies the information type. |
| I_content | The text string representing a piece of information. This can be a single entity (unstructured text) or an XML document. |
For the time being, the following information types (I_type) will be needed.
| Type | Connected to | Description |
|---|---|---|
| DSKEY | dataset | Dataset key (also called directory key or dirkey) as provided by the user. Single entity |
| LOCATION | dataset | Location. Single entity. Absolute path to the directory under which all files belonging to the dataset are found. The files may be found directly in the location directory, or in any subdirectory of the location directory at any level. |
| CATALOG | dataset | Partial URL to a THREDDS dataset. Single entity. Combined with the file name, this URL can be used to access the content of a file through a TDS server. It can also provide the URL that points to the THREDDS catalog containing the METAMOD dataset. |
| WMS_URL | dataset | URL to the WMS service that can display data from the dataset. Single entity. |
| WMS_XML | dataset | XML document that describes available alternatives for displaying the dataset in WMS. For example, the parameters that can be displayed. Each parameter may have a palette (for example “BOXFILL/redblue”) found in a style element in the GetCapabilites document. If no palette is found, a default palette is used for the parameter. |
| SUBSCRIPTION_XML | dataset and user | XML describing details of a subscription on the dataset set up by the user |
| Additional information types may be added later, for example to implement projection information: | ||
| PROJECTION_XML | dataset | XML document used to represent reprojection information. The document contains, among other things, each projection the user has asked for (“Lat/Long”, “Stereo” etc.). Each projection contains attributes: method, projString, xAxis, yAxis and toDegree. |
File
| DS_id | Dataset this file belongs to. Part of primary key. |
|---|---|
| F_name | Local path to file. The full path is given by “LOCATION/F_name” where LOCATION is the dataset LOCATION found in the Info table. Part of primary key. |
| F_timestamp | Timestamp of last change |
| F_size | File size (bytes) |
| F_status | Status (OK or errors) |
| F_errurl | URL to error report (if errors) |
This table is used to display recent changes to the data provider. It will not contain a complete inventory of files in the repository. This table will be purged (rows with old timestamps removed) periodically.
API design
This paragraph defines a set of subroutine/function calls that are used to read and write information to/from the user database. These functions will be implemented in PHP and/or Perl as needed.
The functions are defined as methods in a Userbase class. Inside a Userbase object, there may be a current user and a current dataset. The current user will always own the current dataset. There may also be a current file that will belong to the current dataset.
Open/close functions
| Method | Purpose | Parameters |
|---|---|---|
| new | Create a new Userbase object and set up a connection to the User database | OUT: Userbase object reference |
| close | Save any pending changes to the database, and close the connection | None |
| revert | Revert any changes to the database made by this Userbase object. Close the database connection. | None |
User functions
| Method | Purpose | Parameters |
|---|---|---|
| user_find | Search for an existing user in the database and make him/her the current user. | IN: User E-mail address, application id (A_id). |
| user_create | Create a new user and make it the current user. | IN: User E-mail address, application id (A_id). |
| user_set | Set user properties for the current user | IN: Property name (one of 'U_name', 'U_password', 'U_institution', 'U_telephone', 'U_session'), property value |
| user_get | Get user properties for the current user. | IN: Property name (one of 'U_name', 'U_password', 'U_institution', 'U_telephone', 'U_session'). OUT: property value |
| user_first | Make the first user in the database the current user. | OUT: TRUE if found, FALSE if no users exist. |
| user_next | Make the next user in the database the current one. | OUT: TRUE if found, FALSE if already last user. |
Dataset functions
| Method | Purpose | Parameters |
|---|---|---|
| dset_create | Create a new dataset and make it the current dataset. The current user will be the owner of the new dataset. | IN: Dataset name, dataset key. |
| dset_find | Find a dataset in the database and make it the current dataset. | IN: Application id, dataset name. OUT: true if the dataset is found, false otherwise. |
| dset_first | Make the first dataset (owned by the current user) the current dataset | OUT: true if found, false if no such dataset exists. |
| dset_next | Make the next dataset (owned by the current user) the current dataset. | OUT: true if found, false if already last dataset. |
Information functions
Functions for reading and writing rows in the Info table. Uses the concept “current infoset”. The current infoset is a subset of the rows in the Info table given by how the rows are connected to the current user and/or the current dataset. In addition, all rows in the current infoset must represent the same information type (I_type).
| Method | Purpose | Parameters |
|---|---|---|
| info_set | Define the current infoset | IN: 1. Information type. 2. Keyword that tells how the infoset shall relate to the current user and/or current dataset (values: USER, DATASET, USER_AND_DATASET). OUT: Number of rows (N) in the infoset, or FALSE indicating error. |
| info_get | Get information from the current infoset. | IN: Index into the infoset (0 to N-1). OUT: Value of I_content field (single entity or XML). |
| info_put | Add or replace content fields in the current infoset. | IN: 1. Value of I_content field (single entity or XML). 2. Index into the infoset (0 to N-1). If this parameter is missing, a new row in the infoset is created. This row is given the index N, after which N is incremented. |
File functions
| Method | Purpose | Parameters |
|---|---|---|
| file_find | Search for an existing file (owned by the curent dataset) and make it the current file. | IN: File name (F_name). OUT: true if found, false otherwise. |
| file_create | Create a new file (for the current dataset) and make it the current file. | IN: File name (F_name) |
| file_set | Set file properties for the current file | IN: Property name (one of 'F_size', 'F_status', 'F_errurl'), property value |
| file_get | Get file properties for the current file. | IN: Property name (one of F_name', 'F_size', 'F_status', 'F_errurl', 'F_timestamp'). OUT: property value |
| file_first | Make the first file (in the current dataset) the current file. | OUT: true if found, false if no files exist. |
| file_next | Make the next file in the database the current one. | OUT: true if found, false if already last file. |