Database Definition and 143 Threads

HI, I am looking to find a table of galaxies, their masses, types, black hole mass and dark matter content. Does anyone know if such a place exists anywhere on the internet? I'm trained in physics but is not a physicist - more a hobbyist. Any suggestion that you might have will be greatly...

Hi, I've been working on a 3D rendering web application and am considering creating a database of JSON files. Currently I create a JSON file of data in Mathematica, then run Dropbox to load the JSON file into Dropbox and manually created the web link. I then have to manually add a url to my...

Hi all, Just curious on whether temporal databases are designed in the same way as "standard" relational databases, so that queries on temporal databases are wffs in temporal logic , i.e., using Until, Release and all other unary operators , and the query outputs is the set of models for the...

Hi all, I successfully created (scripted) a database in MS SQL Server 2012. My problem is that while the database itself is listed in the object explorer , the tables from the database are not. The database I scripted did not contain actual data, i.e., there were no 'Insert' statements. Is this...

Hi All, I have been asking around on the "upgradeability" or scalability of GUI -based databases, e.g. Access (using QBE) vs scripted ones, e.g., back-end SQL -based databases (no C# or PHP -based interface). I keep hearing scripted ones are preferrable in the sense of being easier to...

Hi all, I have a bunch of legacy files I am trying to import directly into an .sql database. Is there a way of doing this other than by using Microsoft's import/export Wizard?

I need hexane, MEK and EA densities at 40 degrees. Do you know a good database where to find them?

HI, Do you have any suggestion for a good solubility database? I tried IUPAC-NIST but I can't find the data I need there (water-toluene, water-hexane, water-MEK mixtures at 40°C). I am also looking for the densities of the pure solvents at 40°C. Thank you

Homework Statement R(ABCDEF) D->F AB->C E->F C->BD D->E Decompose R into dependency preserving 3NF Homework Equations F = {D->F, AB->C, E->F, C->BD, D->E} The Attempt at a Solution My attempt is to first construct the minimal basis for the FD set F, which is G={A->C, E->F, C->B, C->D, D->E}...

Hi All, Just curious as to what those with experience in creating databases believe is the best method when renaming databases: using Apex SQL , which (supposedly) automatically checks for dependencies or just sitting down , looking at the dependencies and doing the changes one by one as needed...

Could use some help figuring out the error Operand type clash: numeric is incompatible with uniqueidentifier which points to the specified line below CREATE PROCEDURE AddPartner @name NVARCHAR(50), @email NVARCHAR(254), @new_guid UNIQUEIDENTIFIER OUTPUT AS BEGIN SET NOCOUNT ON...

I need the molar absorptivity data of chromate and dichromate ions at various wavelengths, can anyone suggest a database or something like that?

Hi all :I have the table Emp (EmpNum PK, EmpLastNM, EmpEducation, EmpDependent, EmpEducation,...EMpHireDate) which I want to normalize and then I want to do an ERD for it. I must break this into tables one for which , it seems, I cannot have a non-null PK: Now EmpDependent is both...

Hi all, I am learning DDL ( as opposed to GUI ) table design in MSSL2014. EDIT I am given a table printout and I want as an output the(a) DDL code that would output the given table. Sorry, I don't have a scanner nor the original file in my PC, I have a table diagram in a piece of paper. I...

The only way to recover is from media backup? I know I cannot "rebuild" system datafile, but if I don't have a backup - I know shame on me! - Is there anyway to recover database?

Can not open database file. When you open a written "Application Error" and all. I tried to import objects into a new database. Tables and queries were imported without a problem, but on the forms, reports and modules gives the same error. Standard recovery says that all recovered, but no result.

Hi All, The "best practices" in RDB on 1:1 relations between entities are that the two entities E1, E2 should be merged into a single one by default, i.e., unless there is an overwhelming reason to keep them separated. Can someone provide illustrating examples of when the two entities...

Hi, say we have entities A,B,C in a Relational Database. Is there a sort-of operational algebra that allows us to determine that if, say, A and B are in a many-many relation and B and C are in a 1-many relation, then A,C are in a certain relationship, i.e., a composition algebra between...

I know the web databases were one can plot index of refraction and also transmittance of a material as a function of the wavelength. But these databases are only either for wavelength shorter than 41nm or greater than 200nm. If there a website similar to mentioned below for the UV and XUV...

Hi! I was physics student in Switzerland, but was unsuccessful because of several Army duties in atomical-chemical troups. Physics and chemistry were my passions. Since, I re-oriented myself in computer science as a learner, and discovered a new passion in data management (nowadays databases...

Hi all, I guess now I am at the different end, after having replied to many requests for info on books. I do not have access ( ha-ha) to a library, though I do have access to a bookstore. I am looking for an intermediate-to-advanced book in Database. I have covered the basics: Normalization...

I am looking forward to joining discussions here. My Backgroud is 2 years "applied physics", 5 years education for teaching in visual communication (art), 15 years experience as a database software developer. Now I am looking for a job as a software tester. Software Testing is similar to being...

Hi, Where can I find a database with the mass distribution and its movement in the well-known universe? Best wishes, Jens

Hi All, Say we have a relation R ( i.e., a table in a relational DB ), which has a primary key PK, but R is not in 1 NF. I guess we then conclude that PK _does not_ functionally-determine the table, since, after the table is put in 1NF, PK is o longer the primary key, right? It seems...

I am pulling my hair trying to find a straight answer to this, after looking it up in different books, websites: Say we have a many-to-many relationship in a RDB (Relational DB). Is there a standard way of creating a junction, bridge, etc. table? From what I know,. the bridge table will contain...

Hi all, hope this is the right forum. Please feel free to move it otherwise: I am confused on whether functional dependence can be determined uniquely by the particulars of a given table, or if it is determined in a more general sense So I have my relational table. Let A,B be attributes ...

Hi a probably dumb question on Referential Integrity: I think I understand the basic idea/motivation for it, but one thing I am confused about is this: just when/how do we declare a column in a given table T' to be a foreign key related to the primary key for table T? Is it when we...

Hi all, Say we have a collection T_1, T_2,..., T_n of tables. I would like for any pair to be related. Would it work if I where to select any field, say the primary key PKT_1 for T_1 and insert it (albeit artificially) meaning include it as an attribute in every other table? If we did this...

Hi All, I know that if we use Select * , then the fields in the table will appear in the same order as listed. Same if we list all the fields manually, as in Select field1, field2,.., fieldn . Is it true that the order of the fields is preserved always (I can't think of other cases at this...

Hi, just curious about the difference between the " Sort By " and " Order By" commands in database. I assume Sort by is used in QBE and "Order by" is used in SQL ? While we're at it, how about "Group By"? Thanks.

Though one of my many internet searches, I ran across Hierarchical Data Formats (HDF) last year. It seems interesting but I feel like I'm in over my head a bit. I believe that some people here have use it and I'm looking for advice on getting started, what to watch for and how it's different...

I am doing a ER Diagram for a class and having a lot of trouble with a specific piece of the sentence. Anyway, here is the business requirements we are diagramming: The video rental company has several branches throughout the USA. The data held on each branch is the branch address made up of...

I have a list of contacts like this: Name ,Address:House ,Island ,Atoll 7777777 Name ,Address:House ,Island ,Atoll 7777777 Name ,Address:House ,Island ,Atoll 7777777 I have a large number of these and I want the details to be separated to different columns. Is there any program which...

I am a programmer and physics fan. A speaker (Lawrence Krauss?) at https://origins.asu.edu/events/great-debate-parallel-realities-probing-fundamental-physics (not on youtube yet) said physics theories beyond the standard model are an under-determined problem. There are 7,000 theories that fit...

Hi, I am looking for online molecular emission spectra database for spectroscopic analysis of plasma. It would be great if searching in it is based on a wavelength of spectral lines/bands. For atomic spectra I found this database: http://physics.nist.gov/PhysRefData/ASD/lines_form.html But I...

Does anyone have a good tutorial or start-up advice for building a database in Python? The only database software I've ever used is Microsoft Access, but I've heard it's possible to build databases in Python. I was thinking I'd start off with a simple database: a few tables that can draw...

How would the CPU, RAM and disk storage of a Database server affect the performance of the Database?

hi everyone , i downloaded SQLite files , i have in c:\windows\system32\sqlite 3 files: 1- sqlite.exe 2-sqlite.dll 3-sqlite.def my problem is that i can't create a database or open the one i created by the administrative tools .. as one of the website said that the way to create a...

I am using python to get tuples from a db. I am doing cur.execute("Select Statement"); I use cur.fetchall to get the tuples. My question is how do you iterate over the returned tuples and store the columns into an array? I want to iterate over n tuples, not all the returned results...

Hello all, What is mean the Ritz Wavelengths in the NIST Atomic Spectra Database? Why the Ritz or Observed value for some Wavelength are very different? Thanks, Lil

Hello Guys, So I'm trying to build a database of organic compounds that are of interest to the pharmaceutical industry. Most importantly compounds containing heteroatoms (>= 15% by mass). Where do i start!? any good websites or books, with a useful appendix you can tell me about? I would...

I am typing up a latex document and I need to find roots of unity, lots of them, for numbers like say 42. I was just wondering if anyone knew of a database that had this stuff on hand rather than having to do it all by hand and worrying about having made some stupid algebra error.

Hello,everyone! I want to know if there is database which can tell me the energy level diagram of atom. I have consulted NIST Atomic database,but I can't find energy level diagram. so anybody can help me ? I WANT to get the energy leverl diagram like hydrogen atom in modern books(potential...

Mod note: Instead of using HTML FONT and SIZE tags, just put [ code ] and [ /code ] tags around your code. Hi everyone. I have no idea how databases are usually done, but I figured I'd try to write an advanced I/O database in c++, but I wanted to make a database class that's fairly universal...

I'm choosing a database to write high-frequency time series data onto and have narrowed it down to MongoDB, Kyoto Cabinet or HDF5. I will be inserting 1200 rows of 8 entries per second, cumulating about 5 GB of data per day I'm estimating. Does anyone have experience between the three and...

Greetings I have been working on database collection, and I'm trying to take it to the next level, as a calculator based on the pre-entered information The information would consist of many variable factor (around 8) This is only an example, and not related to the real statistical data...

After you have analyzed the existing material used by the company for their day-to-day duties, the current Access database, and the additional requirements that the current system does not meet, the following requirements entity/attributes have been compiled: Customer information is tracked...

I need to create a system using heterogeneous database. I must use at least 4 different database. My choice would be MySQL, MS SQL Server, Oracle and PostgreSQL since these are among the most popular and matured database or if you have any database that is more suitable please tell me...

I am a graduate student who has basically no experience programming but I would like to learn so I decided to give myself a project. What I would like to do is build a web application that can plot data (2D & 3D) from a database. Once I get that far I would like to have the web application...

Wasn't sure about where else to post this so I posted it here : I got into an argument with my friend about google search being a DBMS, I disagreed because it doesn't fit the definition that we were given or the one on wikipedia and a few more websites. All that google search does it query a...