Re: [GENERAL] TOAD-like query builder for PostgreSQL?
Lightning Admin sounds good, but can it be used with databases other than postgreSQL? It's always nice, when investing time learning a tool, if it can be used elsewhere. ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
[GENERAL] TOAD-like query builder for PostgreSQL?
I really like TOAD for building Oracle queries. Is there a TOAD-like, FOSS query builder for PostgreSQL? ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [GENERAL] Null and Void() - Or, Abandon All Hope Ye Who allow NULLs?
'Scuse my broken english and ungrammatical gibberish in my last missive. That's what I get for posting before my first cup of coffee for the day. I'm serious about nulls though, and am wondering if Date and Pascal, perhaps, are the gibberish ones on this particular issue. The insistence on no nulls, anywhere, any time, for any reason, seems--from a practical vantage--unreasonable. ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
[GENERAL] Null and Void() - Or, Abandon All Hope Ye Who allow NULLs?
Date and Pascal hate nulls. One even goes so far as to say that if you permit NULLs in a database, then the results from *every* query is suspect. So they turn perform backflips suggesting ways to avoid nulls. None, so far, seem appealing. To me, nulls are quite useful in the Real World. For instance, there may be a lot of immediate value for end users in committing a row that has a few nulls (e.g. as in not yet collected), rather than slavishly follow a rule that says Thou Shalt Not commit a row with nulls. Can't the intelligent practitioner simply proceed carefully with queries when nulls are involved? With group functions at least, I believe nulls are ignored. In Oracle, you can use NVL() to force group functions to recognize. What about simply doing an IS NULL test in the code when any table that allows nulls in involved in a query? What precisely has Date and Pascal's knickers in such a twist? The fact that ad hoc queries from random, unintelligent users could give strange results? What if one has control over the queries performed through a GUI or application? Doesn't the problem disappear, presuming the programmer is aware of the issue and the application is well documented? What are some of the best ways to deal with the issue of nulls potentially resulting in questionable query results short of disallowing them? Storing some sort of coded or numeric value that represents UNKNOWN or NOT APPLICABLE. ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [GENERAL] Best open source tool for database design / ERDs?
Can Druid reverse engineer an Access 97 MDB file, say, through an OBDC connection? I would like to replicate the schema from an Access 97 database, then be able to forward engineer to PostgreSQL and other databases. If Druid can't reverse engineer, can another open source tool do the job? Thanks very much. ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [GENERAL] Best open source tool for database design / ERDs?
Bjørn T Johansen wrote: > Yes, that is annoying But you can remove the legend by right clicking on > the name of > the ER and choosing Properties.. Under Legend, you can change Location to > None; > that will remove it... Thanks Bjorn. I'll give that a try. Hopefully that will be turned off by default in the next release. It's a nice program. Using DIA + add-ons to do the same thing seemed inelegant. Although I hope the DIA project continues. Needs to be added to Open Office. Dana ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
Re: [GENERAL] Fabian Pascal and RDBMS deficiencies in fully
Lots of great conversation here. Thanks to all for participating. David, you wrote: >Be aware that Pascal, along with Date and Darwen, are...how do I put >this gently...cranks. They've been getting more strident and >irrational as the decades go by. I can't speak to that statement directly. Indirectly, however, the sources Pascal cites in the body of the text (if I had to guess, and I do because I'm too lazy to count them all) seem to be ~90% works by C.J. Date. So it seems chiefly to be a distillation of Date's ideas, e.g. potentially a cloistered treatise. Is Pascal an academic who doesn't have real world knowledge gained from having logically and physically designed, then brought to production, monitored, refined, and tuned databases, and has answered to end users, for a wide variety of customers and projects? His book's subtitle is: "A Reference for the Thinking Practitioner." If he is not himself a practitioner out there in the trenches, doing the best with whatever technology presently exists, then I'm slightly less interested in what he has to say, although I appreciate what he's trying to do. But I don't want to dwell on the OUGHT in terms of future technology; I want to dwell on the IS. Pleas that we ought to demand better technology are all to the good - Is there a good book out there about DB design written *by* real-world practitioners, *for* real-world practitioners that addresses Pascal and Date's concerns, yet focuses on the technology we have to live with today? Something vendor-neutral if possible. Dana ---(end of broadcast)--- TIP 6: explain analyze is your friend
[GENERAL] Any *real* reason to choose a natural, composite PK over a surrogate, simple PK?
In the book "Practical Issues in Database Management", Fabian Pascal notes three reasons for choosing one PK over another - familiarity, stability, and simplicity. He notes further that those influenced by OO db design tend to use simple, surrogate keys for all PKs in all databases they design; that this is not *precluded* by relational theory, but that there's somehow something illicit about it. Today at least, and why I ask, I think it's a good rule of thumb to create surrogate keys for almost all tables. "Familiarity" seems like a spurious concern, and a poor tradeoff against both stability (guaranteeing you are uniquely identifying rows) and simplicity (with queries, and others intuiting your design). What am I missing? Why use a composite key *ever* aside from "familiarity?" Could someone give a real-world example where "familiarity" is a compelling reason to choose a composite PK, and trumps stability and simplicity? Stability seems to be the single-most important factor to consider. If the database can't uniquely identify a row, what's the point? Choosing a surrogate key guarantees stability. Dana ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [GENERAL] Any *real* reason to choose a natural, composite PK over a surrogate, simple PK?
If one decides to use a composite key, beyond how many attributes should one seriously consider creating a surrogate key instead? 4? 5? Less? I have seen a composite key composed of 5 attributes and thought - why? What's the value over a surrogate key? I guess choosing a candidate key (presuming the candidates are legitimate candidates) is at least partially a matter of taste. What taste would compel people to choose composite keys composed of more than 2-3 attributes? ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
[GENERAL] Fabian Pascal and RDBMS deficiencies in fully implementing the relational model
I'm reading, and enjoying immensely, Fabial Pascal's book "Practical Issues in Database Management." Though I've just gotten started with the book, he seems to be saying that modern RDBMSs aren't as faithful to relational theory as they ought to be, and that this has many *practical* consequences, e.g. lack of functionality. Given that PostgreSQL is open source, it seems a more likely candidate for addressing Pascal's concerns. At least the potential is there. Some questions: 1) Is PostgreSQL more faithful to relational theory? If so, do you find yourself using the additional functionality afforded by this? e.g. does it really matter to what you do in your daily work. 2) If PostgreSQL is *not* significantly more faithful to relational theory than commercial RDBMSs, is it at least on the road to becoming more faithful? 3) If PostgreSQL is not on the road to becoming more faithful to relational theory and purity, why not? Is it due to the fact that various SQL standards are themselves not fully faithful to relational theory, and most RDBMSs have as a primary design goal to be faithful to standards (which Pascal implies *are* relationally deficient)? 4) Which database, commercial or non-commercial, is most faithful to relational theory itself, or is headed in that direction the quickest? Dana ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
Re: [GENERAL] Best open source tool for database design / ERDs?
> I have used Case Studio 2 (fine, weak on documentation generation), and > PowerDesigner by Sybase (truly excellent! but $$$) > John Thanks John. I've been playing with Druid and it seems to be able to do what I need it to do. It wasn't immediately intuitive to use, but the functionality is there. To Druid users, or those who've tried and rejected Druid, what feature deficiencies do you see Druid as having? So long as Druid continues to be developed, I think I'll stick with it. Here's one Druid "annoyance" One real pain with the ER Diagram is that it seems to insist on including, and often inconveniently repositioning, a little non-entity yellow box that says Unamed. I think it's a color legend. Anyone know how I can get rid of it? Other than that, I'm delighted with it so far. The auto-DML creation for whichever database I choose is very cool. Dana ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [GENERAL] Best open source tool for database design / ERDs?
What about OpenOffice Draw 2.0? Can this do ER / UML diagrams that one can then use to forward engineer DDL statements? How does DIA compare to Draw, and wouldn't it be better to roll DIA into OpenOffice? I love OpenOffice and use it as an MS Word / MS Excel replacement. Works great, since it can read/write MS formats. ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [GENERAL] Best open source tool for database design / ERDs?
Bjørn T Johansen wrote: > Have you tried Druid (http://druid.sourceforge.net/index.html) ? > It does anything a good ERD designer do and it's free... Thanks Bjorn. I have downloaded it but not tested it yet. I will test it in the next few days. DIA doesn't seem like a good choice. Did somebody say Druid can do forward engineering for PostgreSQL? I'm a little concerned about stepping over dollars to pick-up pennies so to speak. If Druid does about as much as the commercial diagramming products do, then I will use it. However, if there is a non-open source diagrammer that is USD $200 or less that does a lot more, or does what it does a lot better - e.g. it makes me a lot more efficient, then I would rather pay for the commercial tool. What inexpensive (~USD $200 or less) ERD tools are out there, and are they a lot more feature-rich than Druid? Thanks. Dana ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [GENERAL] Best open source tool for database design / ERDs?
tedia2sql for DIA seems pretty strange, in that it seems to require you to use UML diagrams, rather than ER Diagrams, to forward engineer a database - e.g. output DDL statements. Am I misreading what tedia2sql does, or is does one have to use repurpose UML diagrams to get DDL statements created? I was a little disappointed with the ER Diagram functions of DIA. Looks like you can only add a few properties at most given the way it is structured - having circles radiating out from the Entity. There's only so much screen space... then there's no way to specify a SQL ANSI data type from what I recall. Is there a commercial tool that's less than $200 which kicks the *ss of any of these open source solutions? I'd rather use something free, but not if it doesn't do what I want it to do easily. I like the Open Office apps like Writer and Calc. Calc in particular does everything Excel does - at least everything I've ever used Excel for. Seems like the open source data modeling tools aren't feature-rich quite yet. Dana ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [GENERAL] Best open source tool for database design / ERDs?
Anyone here used both DIA and schema export extensions for it as well as the Eclipse ERD plug-in for creating and exporting schemas - I mean outputting DDL statements in PostgreSQL? Or Druid? Which do you like best and why? Thanks. ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [GENERAL] Best open source tool for database design / ERDs?
Thanks for all the great suggestions. Dana ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [GENERAL] Best open source tool for database design / ERDs?
Anyone know if DIA will generate CREATE TABLE statements from an ER diagram? I'd like to have a program where I can create my db design, then be able to instantiate the design in PostgreSQL as well as MySQL. I'll pay for a good commercial tool if it costs less than USD $100. Thanks. ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [GENERAL] Best open source tool for database design / ERDs?
Thanks Thomas. That's too bad about DB Designer. I didn't realize it had been abandoned. What do y'all think of DIA? ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [GENERAL] Best open source tool for database design / ERDs?
Thanks. What about DIA - http://www.gnome.org/projects/dia/ ...or DB Designer - http://fabforce.net/dbdesigner4/ (this one claims to be feature-equivalent, or in the sphere of, products like Oracle's Designer, ERWin, and Rational Rose. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
[GENERAL] Best open source tool for database design / ERDs?
What open source tool do people here like for creating ER diagrams? ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
