I am doing dozen of queries per day, and I admit sometimes I miss the context of the user's demand.
I would like to know if you have any tips to check / double check, if a SQL query is really doing what the context is asking.
For example, I have this context :
retrieve the firstname of 10 male students from the school "great_school" having 21 years old.
For this context I would write a pseudo query like this :
SELECT st.firstname
FROM studient st
JOIN school_studient sc_st ON sc_st.studient_id = st.id
JOIN school sc ON sc.id = sc_st.shool_id
AND sc.name = "great_school"
WHERE st.age = 21
AND st.sexe = "male"
LIMIT 10
How to be sure that this query is really doing what the context asked ?
It isn't about using EXPLAIN to check if the query is valid, it is about checking that the query has all the conditions needful.
Is there any tools who is able to read pseudo query and tell what it does in human language ?
I was thinking about a paper checklist with 2 columns : "fields to select" and "criterias", and then I tick everytime one item is in the query.
But isn't there more advance tools than a piece of paper ?
Your question is asking for a recommendation for a software product, which is off topic on SO, but you might have more luck here.
However, I would focus more on a process than on a tool. I find it really helpful to work with sample data sets, and ask the end user to mark up what should and should not be included. The challenges in interpretation are usually much more around "what's in/out", "how do we aggregate (what's the group-by)" and "how do we sort" (your example grabs 10 random students).
If you can build a sample data set, and ask your users to say "I want these records to be included, those excluded", and "I want you to aggregate this column for every change in that column", you get a much higher quality specification. Once you find problems in the specification, you can adjust the sample data set to avoid that problem in future...
I have a survey that ask the question of availability via check boxes like so:
I am available (please check all that apply:
[] Early Mornings
[] Mid Mornings
[] Early Afternoons
[] Mid Afternoons
[] Evenings
[] Late Evenings
[] Overnight
That I need to translate into a SQL database. My question is: What is the best way to store this data under one column? I was thinking of a 7 digit bit storage like: 0010001 (Indicates the candidate is only available during Early Afternoons and overnight). Is there a better way? Thanks for any opinions!
A separate table for the options and a "join table" of options to the candidate. The other solutions/suggestions will impede data integrity and performance in a relational database. If you've got another DB it might be different but don't do anything other than the relational table if you're using SQL.
Pipe delimited flags.
Make the column a fairly wide text column, then store:
'Early Mornings|Evenings|Overnight'
if those 3 choices were selected.
(Note: I do agree with the other answer that it is likely better to use separate columns, but this is how I'd do it if there were a good reason to want just 1 column)
Is there any particular reason the results need to be stored inside one column? If so, your solution is probably the best way EDIT: If you are going to be querying this data your solution is the best way, otherwise follow the other answer using "|" to separate the strings in one long varchar field, though anyone looking at that data is going to have no clue what it means unless they've taken the time to memorize each question in order.
If it doesn't need to be all in one column I'd recommend just creating a column for each question with a bit value similar to what you already want to do.
I am very new to VBA and SQL and am trying to learn. I have a MS Access project that requires a VBA script that prompts the user to input two table names and numerous field names and create a SQL query utilizing those the names.
The specific SQL query I'm trying to use is below.
SELECT
A.user_index, A.input1, B.input1, A.input2, B.input2, A.input3, B.input3, B.input4,
A.input4, A.input5, B.input5
FROM
table1 AS A
LEFT JOIN
table2 AS B ON A.user_index = B.user_index
WHERE
(((A.input1) <> [B].[input1)) OR
(((A.input2) <> [B].[input2])) or
(((A.input4) <> [B].[input4]));
The overall purpose of this is to have a script that will be able to list fields for comparison that is applicable with any database. I know this is probably a relatively easy solution. However, I have no idea where to start.
My first instinct is to say "What have you tried so far?", but as you said, you don't know where to start.
It sounds like you need to first prompt the user for several field and table names, then build a query based on those values. I recommend first outlining exactly what you want your script to do. Maybe something like:
Declare variables to hold the values.
Prompt the user for each of the values and store them in the variables.
2a. After the user enters a value, make sure it is valid. If not, do something accordingly.
Declare a variable to hold your SQL query.
Construct the query.
Run the query.
This is obviously just an example. Break down each step into "baby steps" as much as possible.
It's a good idea to ask yourself how unique these baby steps are to your particular situation (hint: they almost certainly are not unique). If they aren't, then they have probably been solved tens of thousands of times already, so you have a very good chance of googling your questions.
If you still can't find an answer to how to do a particular step, feel free to ask here. Just remember to include your code even if it is broken :)
I need to get data in multiple row of one column.
For example data from that format
ID Interest
Sports
Cooking
Movie
Reading
to that format
ID Interest
Sports,Cooking
Movie,Reading
I wonder that we can do that in MS Access sql. If anybody knows that, please help me on that.
Take a look at Allen Browne's approach: Concatenate values from related records
As for the normalization argument, I'm not suggesting you store concatenated values. But if you want to join them together for display purposes (like a report or form), I don't think you're violating the rules of normalization.
This is called de-normalizing data. It may be acceptable for final reporting. Apparently some experts believe it's good for something, as seen here.
(Mind you, kevchadder's question is right on.)
Have you looked into the SQL Pivot operation?
Take a look at this link:
http://technet.microsoft.com/en-us/library/ms177410.aspx
Just noticed you're using access. Take a look at this article:
http://www.blueclaw-db.com/accessquerysql/pivot_query.htm
This is nothing you should do in SQL and it's most likely not possible at all.
Merging the rows in your application code shouldn't be too hard.
I am trying to determine what the best way is to find variations of a first name in a database. For example, I search for Bill Smith. I would like it return "Bill Smith", obviously, but I would also like it to return "William Smith", or "Billy Smith", or even "Willy Smith". My initial thought was to build a first name hierarchy, but I do not know where I could obtain such data, if it even exists.
Since users can search the directory, I thought this would be a key feature. For example, people I went to school with called me Joe, but I always go by Joseph now. So, I was looking at doing a phonetic search on the last name, either with NYSIIS or Double Metaphone and then searching on the first name using this name heirarchy. Is there a better way to do this - maybe some sort of graded relevance using a full text search on the full name instead of a two part search on the first and last name? Part of me thinks that if I stored a name as a single value instead of multiple values, it might facilitate more search options at the expense of being able to address a user by the first name.
As far as platform, I am using SQL Server 2005 - however, I don't have a problem shifting some of the matching into the code; for example, pre-seeding the phonetic keys for a user, since they wouldn't change.
Any thoughts or guidance would be appreciated. Countless searches have pretty much turned up empty. Thanks!
Edit: It seems that there are two very distinct camps on the functionality and I am definitely sitting in the middle right now. I could see the argument of a full-text search - most likely done with a lack of data normalization, and a multi-part approach that uses different criteria for different parts of the name.
The problem ultimately comes down to user intent. The Bill / William example is a good one, because it shows the mutation of a first name based upon the formality of the usage. I think that building a name hierarchy is the more accurate (and extensible) solution, but is going to be far more complex. The fuzzy search approach is easier to implement at the expense of accuracy. Is this a fair comparison?
Resolution: Upon doing some tests, I have determined to go with an approach where the initial registration will take a full name and I will split it out into multiple fields (forename, surname, middle, suffix, etc.). Since I am sure that it won't be perfect, I will allow the user to edit the "parts", including adding a maiden or alternate name. As far as searching goes, with either solution I am going to need to maintain what variations exists, either in a database table, or as a thesaurus. Neither have an advantage over the other in this case. I think it is going to come down to performance, and I will have to actually run some benchmarks to determine which is best. Thank you, everyone, for your input!
In my opinion you should either do a feature right and make it complete, or you should leave it off to avoid building a half-assed intelligence into a computer program that still gets it wrong most of the time ("Looks like you're writing a letter", anyone?).
In case of human names, a computer will get it wrong most of the time, doing it right and complete is impossible, IMHO. Maybe you can hack something that does the most common English names. But actually, the intelligence to look for both "Bill" and "William" is built into almost any English speaking person - I would leave it to them to connect the dots.
The term you are looking for is Hypocorism:
http://en.wikipedia.org/wiki/Hypocorism
And Wikipedia lists many of them. You could bang out some Python or Perl to scrape that page and put it in a db.
I would go with a structure like this:
create table given_names (
id int primary key,
name text not null unique
);
create table hypocorisms (
id int references given_names(id),
name text not null,
primary key (id, name)
);
insert into given_names values (1, 'William');
insert into hypocorisms values (1, 'Bill');
insert into hypocorisms values (1, 'Billy');
Then you could write a function/sproc to normalize a name:
normalize_given_name('Bill'); --returns William
One issue you will face is that different names can have the same hypocorism (Albert -> Al, Alan -> Al)
I think your basic approach is solid. I don't think fulltext is going to help you. For seeding, behindthename.com seems to have large amount of the data you want.
Are you using SQl Server 2005 Express with Advanced Services as to me it sounds you would benefit from the Full Text indexing and more specifically Contains and Containstable which you can use with specific instructions here is a link for the uses of Containstable:
http://msdn.microsoft.com/en-us/library/ms189760.aspx
and here is the download link for SQL Server 2005 With Advanced Services:
http://www.microsoft.com/downloads/details.aspx?familyid=4C6BA9FD-319A-4887-BC75-3B02B5E48A40&displaylang=en
Hope this helps,
Andrew
You can use the SQL Server Full Text Search and do an inflectional search.
Basically like:
SELECT ProductId, ProductName
FROM ProductModel
WHERE CONTAINS(CatalogDescription, ' FORMSOF(THESAURUS, metal) ')
Check out:
http://en.wikipedia.org/wiki/SQL_Server_Full_Text_Search#Inflectional_Searches
http://msdn.microsoft.com/en-us/library/ms345119.aspx
http://www.mssqltips.com/tip.asp?tip=1491
Not sure what your application is, but if your users know at the time of sign up that people from their past might be searching the database for them, you could offer them the chance in the user profile to define other names they might be known as (including last names, women change these all the time and makes finding them much harder!) and that they want people to be able to search on. Store these in a separate related table. Then search on that. Just make the structure such that you can define one name as the main name (the one you use for everything except the search.)
You'll find that you're dabbling in an area known as "Natural Language Processing" and you'll need to do several things, most of which can be found under the topic of stemming.
Simplistic stemming simply breaks the word apart, but more advanced algorithms associate words that mean the same thing - for instance Google might use stemming to convert "cat" and "kitten" to "feline" and search for all three, weighing the actual word provided by the user as slightly heavier so exact matches return before stemmed matches.
It's a known problem, and there are open source stemmers available.
-Adam
No, Full Text searches will not help to solve your problem.
I think you might want to take a look at some of the following links: (Funny, no one mentioned SoundEx till now)
SoundEx - MSDN
SoundEx - Google results
InformIT - Tolerant Search algorithms
Basically SoundEx allows you to evaluate the level of similarity in similar sounding words. The function is also available on SQL 2005.
As a side issue, instead of returning similar results, it might prove more intuitive to the user to use a AJAX based script to deliver similar sounding names before the user initiates his/her search. That way you can show the user "similar names" or "did you mean..." kind of data.
Here's an idea for automatically finding "name synonyms" like Bill/William. That problem has been studied in the broader context of synonyms in general: inducing them from statistics of which words commonly appear in the same contexts in a large text corpus like the Web. You could try combining that approach with a list of names like Moby Names; I don't know if it's been done before.
Here are some pointers.