If the goal is to learn and to improve your CV, I would install all these systems.
But definitely include Oracle: it's pretty much the gold standard of database systems, and there is always well-paid work. Oracle is to be avoided if you have to pay for the system (it's ridiculously overpriced) but for a developer it is a good skill to have. There is a free developer install.
If you also install the free/opensource systems PostgreSQL, MySQL and SQLite, you can learn how to write programs that talk to the different systems in the same way (=with the same/similar SQL statements). This way you'll learn the differences and specific strengths of each system.
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||