Re: Database internals

Jim Connelley wrote:
>
> Many database work by tracking your database objects, columns, indexes
> etc. in their own master or SYSTEM database. Try this query (MSSQL
> 7.0)
>
> select sysobjects.name,
> syscolumns.colid,
> syscolumns.name,
> systypes.name,
> from sysobjects,syscolumns,systypes
> where sysobjects.id = syscolumns.id
> and syscolumns.xusertype = systypes.xusertype
> and sysobjects.id < 100
> order by sysobjects.id,syscolumns.colid
>
> Does anyone have similar for other databases?

Every DBMS keep track of the system within the system. In the definition of a datbase system (according to Deen) every database system has a description of itself.

In som systems they call it 'master db', in other systems it may carry any of the names 'system catalogue', 'term catalogue', 'data dictionary' and there may be still other names for it. But no DBMS can work without keeping track of its content and in all the systems I have worked with, queries like the one above is possible.

/Serafim Received on Sun Jul 22 2001 - 01:26:33 CEST