MLHT Database

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Documenting the database that contains the text strings for the multinlingual hypertext (mlht) system as well as, on top of it, most other ffii-related data.

News & Chronology


The MLHT database is the set of relational database tables used for describing multilingual documents. It is applied by the MLHT system but is designed to be used by others as well.

As far as ffii is concerned, the tables are implemented in postgresql within the 'ffii' database on genba.

Examples of MLHT database tables are

Some tables contain database metadata, i.e. they define how the actually used tables behave. Such tables include

Metadata in PostgreSQL System Catalogs

feklee: !PostgreSQL already maintains meta data in the form of System Catalogs. These catalogs could be used to replace some, if not all, of the above meta data tables. The advantage when it comes e.g. to documentation is that tools such as psql or phpPgAdmin offer facilities to easily view and modify comments of tables, fields, etc..

phm: We need a script that synchronises metadata between the !PostgreSQL System Catalogs and the flddes tables. It seems to me that there are certain things that each of these does that the other can't replace. Since the !PostgreSQL idocs don't provide examples that allow me to immediately and use the !PostgreSQL metadata, I may be underestimating their power. It would be nice to have some examples in the section below.

feklee: Using a script for synchronizing metadata is not a good solution IMO. Some reasons:

Also, having two sources of meta data is problematic since it introduces redundant data. Thus I propose that the use of views generating MLHT metadata from !PostgreSQL metadata should be investigated.

Example of meta documentation using FLDDES and PostgreSQL System Catalogs

Finding out what the table 'ven' and the field 'ven' mean using MLHT's meta data:

Setting and retrieving documentation from system catalogs is shown in the example below. More information on comments can be found in the chapter Database Management in Practical !PostgreSQL and in the section on COMMENT in the !PostgreSQL documentation.

Opinions by feklee:

00 the database comments are not browsed by end users but by system administrators/programmers/... that are used to having code/data documented in english. 00 If multilingual comments are desired, then we could make up a system that encodes comments in multiple languages in a single string. Such a system could also be used when documenting code e.g. in Perl.

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