normalization

Mysql : should i put my data into 1 table or split per user?

This data is for a holiday cottage's simple accommodation calendars. The data is simple and stores dates when each cottage is booked. The cols would be cottage_id, booked_from_date, booked_until_date and I would expect around 60 rows per user per year * 200-300 users. I should put this is one table right? ...

How to join 1 table twice in the same query and keep results separate

Hi, we're building a scheduler system and have a couple of situations where we're trying to get some notes from a table to display. We've looked at other answers and none seem to quite match this problem. The bookings table holds a numeric reference to both a client note (if present) and a stylist note (if present). The notes table ho...

Does normalization really hurt performance in high traffic sites?

I am designing a database and I would like to normalize the database. In one query I will joining about 30-40 tables. Will this hurt the website performance if it ever becomes extremely popular? This will be the main query and it will be getting called 50% of the time. The other queries I will be joining about two tables. I have a choi...

How to structure (normalize?) a database of physical parameters?

Hello: I have a collection of physical parameters associated with different items. For example: Item, p1, p2, p3 a, 1, 2, 3 b, 4, 5, 6 [...] where px stands for parameter x. I could go ahead and store the database exactly as presented; the schema would be CREATE TABLE t1 (item TEXT PRIMARY KEY, p1 FLOAT, p2 FLOAT, p3 FL...

Populating a foreign key table with variable user input

I'm working on a website that will be based on user contributed data, submitted using a regular HTML form. To simplify my question, let's say that there will be two fields in the form: "User Name" and "Country" (this is just an example, not the actual site). There will be two tables in the database : "countries" and "users," with "user...

How do I display non-normalized data in a hierarchical structure?

My issue is that I want to display data in a hierarchal structure as so: Democrat County Clerk Candidate 1 Candidate 2 Magistrate Candidate 1 Candidate 2 Candidate 3 But I'm retrieving the dataset like this: Party | Office | Candidate -------------------------------------------- Democrat | County Clerk | Candidate 1 Democrat |...

How to put tags inside an html attribute?

Using xslt i want to create an attribute: <span class="tooltip"> <xsl:attribute name="onmouseover"> <xsl:text>javascript:function(</xsl:text> <span class="label">Aggiunta</span> <xsl:apply-tempaltes/> <xsl:text>)</xsl:text> </xsl:attribute> The pr...

Is the set of data always normalized in one form or the other in Databases

Suppose I have a set of data, given the data and the relation schemas can I assume that the set of data is normalized in one form or the other. In my opinion raw data given, has to be normalized into some form. However a discussion with a friend has led to ask me this question here. To expound more on the question, I would say given a s...

Active Record/ORM vs Normal Forms?

Hello, I've been playing around with Active Record a bit, and I have noticed that A.C./ORM always uses the following database model when creating a one-to-one relationship Person id | country_id | name | ... Country id | tld | name | ... No I wondered, isn't this a violiation of the third Normal Form? This clearly states "...

Modeling many-to-one with constraints?

I'm attempting to create a database model for movie classifications, where each movie could have a single classification from each of one of multiple rating systems (e.g. BBFC, MPAA). This is the current design, with all implied PKs and FKs: TABLE Movie ( MovieId INT -- PK ) TABLE ClassificationSystem ( ClassificationSystem...

Insert Registration Data in MySQL using PHP

I may not be asking this in the best way possible but i will try my hardest. Thank you ahead of time for your help: I am creating an enrollment website which allows an individual OR manager to enroll for medical testing services for professional athletes. I will NOT be using the site as a query DB which anybody can view information stor...

Normalize database or not? Read only MyISAM table, performance is the main priority (MySQL)

I'm importing data to a future database that will have one, static MyISAM table (will only be read from). I chose MyISAM because as far as I understand it's faster for my requirements (I'm not very experienced with MySQL / SQL at all). That table will have various columns such as ID, Name, Gender, Phone, Status... and Country, City, Str...

Have 2 separate tables or an additional field in 1 table?

Hello, I am making a small personal application regarding my trade of shares of various companies. The actions can be selling shares of a company or buying. Therefore, the details to be saved in both cases would be: Number of Shares Average Price Would it be better to use separate tables for "buy" and "sell" or just use one table ...

How to SQL compare columns when one has accented chars?

I have two SQLite tables, that I would love to join them on a name column. This column contains accented characters, so I am wondering how can I compare them for join. I would like the accents dropped for the comparison to work. ...

NumPy: how to quickly normalize many vectors?

How can a list of vectors be elegantly normalized, in NumPy? Here is an example that does not work: from numpy import * vectors = array([arange(10), arange(10)]) # All x's, then all y's norms = apply_along_axis(linalg.norm, 0, vectors) # Now, what I was expecting would work: print vectors.T / norms # vectors.T has 10 elements, as d...

database is normalized but the resulting keys are a problem

but the prob is there are relations ships which are so huge that after normalizing they have like a 20 primary keys( composite keys) which are really foreign keys but have to be declared as primary keys to identify the relationship uniquely. so please help? is it correct and i apologize to the expert community for not accepting answers...

Normalizing data with DISTINCT

I have 1,000,000 rows per month per PC generated by some monitoring software. The DataToImport (temporary) table looks like this: EventID int NOT NULL (Primary Key of denormalized table) EventType int NOT NULL -- A enumerated value Computer nvarchar(50) NOT NULL -- Usually computer name When DateTi...

Arrays in database tables and normalization

Hi! Is it smart to keep arrays in table columns? More precisely I am thinking of the following schema which to my understanding violates normalization: create table Permissions( GroupID int not null default(-1), CategoryID int not null default(-1), Permissions varchar(max) not null default(''), constraint PK_GroupCateg...

How can I detect and split words like "Apple 1 & 2" into "Apple 1" and "Apple 2" from a list?

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How would I implement separate databases for reading and writing operations?

I am interested in implementing an architecture that has two databases one for read operations and the other for writes. I have never implemented something like this and have always built single database, highly normalised systems so I am not quite sure where to begin. I have a few parts to this question. 1. What would be a good resourc...