Thank you in advance for your help...
I want to get the parent site list/informatoin for a site based on its ID. There is a site hierarchy described in 2 tables, like this:
table: site
- id (PK)
- name
table: hierarchy
- siteid (PK) (siteid => site.id)
- parented (PK) (parented => site.id)
- topid (topid => site.id)
For example, you may have the following data in the tables:
site:
id,name
0,Earth
1,US
2,NY
3,GA
4,Queens
5,Farmers' Market
6,Buckhead
hierarchy:
siteid,parented,topid
5,4,1
4,2,1
2,1,1
1,0,1
5,6,1
6,3,1
3,1,1
1,0,1
I want to get all the parents of the Farmers's Market sites. There are markets in both Buckhead and Queens.
How do I make SQL walk / recurse up the tree to get something like this if I want the parent list for site id=5?:
site_name,parent_name
Farmers' Market,Queens
Queens,NY
NY,Earth
Farmers' Market,Buckhead
Buckhead,GA
GA,Earth
It occurs to me that there may need to be more than one row in the site table for Farmers' Market, but, I don't think so...
Thanks for your help,
David
Related
I am trying to self-teach myself database management using Murach books, and I found these exercises online but I don't know where to start with the last two. I am using the Alexamara Marina database to complete the following exercises.
Create a query that displays the following for all boats: (1 row)
Total number of boats (name it: number_of_boats),
the maximum rental fee (name it: highest_rental_fee),
the shortest boat (name it: shortest boat)
Modify exercise 3 (the one above) to display the same information by marina rather than as a total of all boats. (2 rows)
I appreciate any help or tips!
EDIT: I am not sure how to attach the Alexamara database file so I am pasting it on pastebin so that everyone can run and create it.(see below)
Alexamara
Yeah I was having trouble with the site letting me paste the link on its own... Sorry
i don't know the structure of the database you're working with, you could get it by using
SHOW COLUMNS FROM boats
i am assuming that the database name is 'boats' and it contains the columns 'fee' and 'length'
SELECT
COUNT(*) AS nuber_of_boats,
MAX(fee) AS highest_rental_fee,
MIN(length) AS shortest_boat
FROM boats;
I am assuming that a boat corresponds to the marina_slip table
Total number of boats (name it: number_of_boats)
SELECT
COUNT(*) AS number_of_boats,
MAX(RentalFee) AS highest_rental_fee,
MIN(Length) AS shorted_boat
from MarinaSlip
Modify exercise 3 (the one above) to display the same information by marina rather than as a total of all boats. (2 rows)
SELECT
COUNT(*) AS number_of_boats,
MAX(RentalFee) AS highest_rental_fee,
MIN(Length) AS shorted_boat,
MarinaNum
from MarinaSlip
group by MarinaNum
I am in the process of developing a database for an automated drink mixing robot, and I'm getting stuck with how to create the database.
In one table, I have a list of every possible ingredient (Coca-Cola, Pepsi, Smirnoff - Red Label, Skyy, etc.). A second table, lists which ingredients are available. A third table specifies the mixed drink recipes. My issue arises with the mixed drink table.
For example, if I wanted to order a Screw Driver, the robot would look to see if any vodka was available, and if any orange juice was available. However, if a drink recipe called for a specific type of vodka (such as Smirnoff - Red Label) I would want the robot to only use Smirnoff and not just any type of vodka.
So, does anyone have any suggestions as to how I could go about developing the database for such an application? I am thoroughly stumped with this one.
Thanks in advance.
It sounds like you need some kind of hierarchy for your ingredients. So you would have "generics" like "cola", "vodka", "rum" etc and then the "brands" like "Coca-Cola", "Smirnoff", "Bacardi" etc
One way of achieving this is with two tables:
Generics
ID - Name
1 - Cola
2 - Vodka
etc
Ingredients
ID - Generic_id - Name
1 - 1 - Coca-Cola
2 - 1 - Pepsi
3 - 2 - Smirnoff - Red Label
4 - 2 - Absolut
etc
Ps This sounds suspiciously like homework. If it is you should tag it as such...
You should add one more table "ingridient category" (ex. fruit juice, vodka, tequila) and reference ingredients table to this with FK. Then alter you receipt table, it should contain category or exact ingridient as a part of receipt.
Then, when robot looks for a ingridients it can decide, if he has exact ingridient or can choose from category list.
Split the ingredients into two tables: ingredient_types (i.e. vodka, juice, soft drink) and ingredients (i.e. Smirnoff, orange juice, cola). In the recipes reference either an ingredient type ("vodka") or specific ingredient ("Smirnoff").
Hey guys,
This is a follow-up to a question that I asked earlier. It is my first time using a relational database and I need help with a quick search string to bring up desired results.
Background information: I'm making a database for my photo portfolio and want to be able to retrieve image links/data via their categories. Each image can be listed in multiple categories.
My database is set-up as follows :
TABLE tbl_images (image_id, image_title, image_location, image_descrip,image_url)
TABLE tbl_categories (category_id,category_name,category_descrip)
TABLE tbl_image_categories (image_id,category_id)
Where one of my images (image_id=1) has two categories (Desert [category_id=1] and Winter [category_id=2]). Which I defined in tbl_image_categories as 1,1 and 1,2.
I also have a few other images that I defined as Desert images [category_id=1].
How would I go about getting which images should be loaded based on the Desert Category?
I tried:
SELECT tbl_images.image_url
FROM tbl_images,
tbl_image_categories,
tbl_categories
WHERE tbl_categories.category_id = 1
Try this:
SELECT DISTINCT tbl_images.image_url
FROM tbl_images,
tbl_image_categories,
tbl_categories
WHERE chad_categories.category_id = 1 //category_id=1 for Desert
AND chad_images.image_id = chad_image_categories.image_id
AND chad_image_categories.category_id = chad_categories.category_id
Lets say we have this MySQL table
name value
author Sabriel Armstrong
author Peter Abhorsen
author Garth Stein
item bell
item book
item sword
item wand
Given these database entries, is there a way to retrieve this values as to get it in the format below? Or is my database modeling wrong?
array(
[author] => array(Sabriel Armstrong,Peter Abhorsen, Garth Stein),
[item] => array(bell,book,sword, wand)
)
MySQL does not have arrays so it's hard to figure out what exact result set you are expecting. In any case, your DB design provides no way to match an author with an item: such information is simply not stored anywhere.
I suppose you'll have a reason to avoid this:
author item
====== ======
Sabriel Armstrong bell
Peter Abhorsen book
:-?
Wow, makes your head spin!
I am about to start a project, and although my mySql is OK, I can't get my head around what required for this:
I have a table of web addresses.
id,url
1,http://www.url1.com
2,http://www.url2.com
3,http://www.url3.com
4,http://www.url4.com
I have a table of users.
id,name
1,fred bloggs
2,john bloggs
3,amy bloggs
I have a table of categories.
id,name
1,science
2,tech
3,adult
4,stackoverflow
I have a table of categories the user likes as numerical ref relating to the category unique ref. For example:
user,category
1,4
1,6
1,7
1,10
2,3
2,4
3,5
.
.
.
I have a table of scores relating to each website address. When a user visits one of these sites and says they like it, it's stored like so:
url_ref,category
4,2
4,3
4,6
4,2
4,3
5,2
5,3
.
.
.
So based on the above data, URL 4 would score (in it's own right) as follows: 2=2 3=2 6=1
What I was hoping to do was pick out a random URL from over 2,000,000 records based on the current users interests.
So if the logged in user likes categories 1,2,3 then I would like to ORDER BY a score generated based on their interest.
If the logged in user likes categories 2 3 and 6 then the total score would be 5. However, if the current logged in user only like categories 2 and 6, the URL score would be 3. So the order by would be in context of the logged in users interests.
Think of stumbleupon.
I was thinking of using a set of VIEWS to help with sub queries.
I'm guessing that all 2,000,000 records will need to be looked at and based on the id of the url it will look to see what scores it has based on each selected category of the current user.
So we need to know the user ID and this gets passed into the query as a constant from the start.
Ain't got a clue!
Chris Denman
What I was hoping to do was pick out a random URL from over 2,000,000 records based on the current users interests.
This screams for predictive modeling, something you probably wouldn't be able to pull off in the database. Basically, you'd want to precalculate your score for a given interest (or more likely set of interests) / URL combination, and then query based on the precalculated values. You'd most likely be best off doing this in application code somewhere.
Since you're trying to guess whether a user will like or dislike a link based on what you know about them, Bayes seems like a good starting point (sorry for the wikipedia link, but without knowing your programming language this is probably the best place to start): Naive Bayes Classifier
edit
The basic idea here is that you continually run your precalculation process, and once you have enough data you can try to distill it to a simple formula that you can use in your query. As you collect more data, you continue to run the precalculation process and use the expanded results to refine your formula. This gets really interesting if you have the means to suggest a link, then find out whether the user liked it or not, as you can use this feedback loop really improve the prediction algorithm (have a read on machine learning, particularly genetic algorithms, for more on this)
I did this in the end:
$dbh = new NewSys::mySqlAccess("xxxxxxxxxx","xxxxxxxxxx","xxxxxxxxx","localhost");
$icat{1}='animals pets';
$icat{2}='gadget addict';
$icat{3}='games online play';
$icat{4}='painting art';
$icat{5}='graphic designer design';
$icat{6}='philosophy';
$icat{7}='strange unusual bizarre';
$icat{8}='health fitness';
$icat{9}='photography photographer';
$icat{10}='reading books';
$icat{11}='humour humor comedy comedian funny';
$icat{12}='psychology psychologist';
$icat{13}='cartoons cartoonist';
$icat{14}='internet technology';
$icat{15}='science scientist';
$icat{16}='clothing fashion';
$icat{17}='movies movie latest';
$icat{18}="\"self improvement\"";
$icat{19}='drawing art';
$icat{20}='latest band member';
$icat{21}='shop prices';
$icat{22}='recipe recipes food';
$icat{23}='mythology';
$icat{24}='holiday resorts destinations';
$icat{25}="(rude words)";
$icat{26}="www website";
$dbh->Sql("DELETE FROM precalc WHERE member = '$fdat{cred_id}'");
$dbh->Sql("SELECT * FROM prefs WHERE member = '$fdat{cred_id}'");
#chos=();
while($dbh->FetchRow()){
$cat=$dbh->Data('category');
$cats{$cat}='#';
}
foreach $cat (keys %cats){
push #chos,"\'$cat\'";
push #strings,$icat{$cat};
}
$sqll=join("\,",#chos);
$words=join(" ",#strings);
$dbh->Sql("select users.id,users.url,IFNULL((select sum(scoretot.scr) from scoretot where scoretot.id = users.id and scoretot.category IN \($sqll\)),0) as score from users WHERE MATCH (description,lasttweet) AGAINST ('$words' IN BOOLEAN MODE) AND IFNULL((SELECT ref FROM visited WHERE member = '$fdat{cred_id}' AND user = users.id LIMIT 1),0) = 0 ORDER BY score DESC limit 30");
$cnt=0;
while($dbh->FetchRow()){
$id=$dbh->Data('id');
$url=$dbh->Data('url');
$score=$dbh->Data('score');
$dbh2->Sql("INSERT INTO precalc (member,user,url,score) VALUES ('$fdat{cred_id}','$id','$url','$score')");
$cnt++;
}
I came up with this answer about three months ago, and just cannot read it. So sorry, I can't explain how it finally worked, but it managed to query 2 million websites and choose one based on the history of a users past votes on other sites.
Once I got it working, I moved on to another problem!
http://www.staggerupon.com is where it all happens!
Chris