Convention has it that table names should be the singular of the entity that they store attributes of.
I dislike any T-SQL that requires square brackets around names, but I have renamed a Users table to the singular, forever sentencing those using the table to sometimes have to use brackets.
My gut feel is that it is more correct to stay with the singular, but my gut feel is also that brackets indicate undesirables like column names with spaces in them etc.
Should I stay, or should I go?
What convention requires that tables have singular names? I always thought it was plural names.
A user is added to the Users table.
This site agrees:
http://vyaskn.tripod.com/object_naming.htm#Tables
This site disagrees (but I disagree with it):
http://justinsomnia.org/writings/naming_conventions.html
As others have mentioned: these are just guidelines. Pick a convention that works for you and your company/project and stick with it. Switching between singular and plural or sometimes abbreviating words and sometimes not is much more aggravating.
Possible alternatives:
IMO using brackets is technically the safest approach, though it is a bit cumbersome. IMO it's 6 of one, half-a-dozen of the other, and your solution really just boils down to personal/team preference.
Another vote for plurals.
I've seen some people use singular, but to me it only matters that it is consistent across the database.
I always thought that was a dumb convention. I use plural table names.
(I believe the rational behind that policy is that it make it easier for ORM code generators to produce object & collection classes, since it is easier to produce a plural name from a singular name than vice-versa)
Guidelines are really there as just that. It's not "set in stone" that's why you have the option of being able to ignore them.
I would say that it's more logically intuitive to have pluralized table names. A table is a collection of entity after all. In addition to other alternatives mentioned I commonly see prefixes on table names...
I'm not suggesting this is the way to go, I also see spaces used a LOT in table names which I abhor. I've even come across field names with idiotic characters like ? as if to say this field answers a question.
This may be a bit redundant, but I would suggest being cautious. Not necessarily that it's a bad thing to rename tables, but standardization is just that; a standard -- this database may already be "standardized", however badly :) -- I would suggest consistency to be a better goal given that this database already exists and presumably it consists of more than just 2 tables.
Unless you can standardize the entire database, or at least are planning to work towards that end, I suspect that table names are just the tip of the iceberg and concentrating on the task at hand, enduring the pain of poorly named objects, may be in your best interest --
Practical consistency sometimes is the best standard... :)
my2cents ---
There is no "convention" that requires table names to be singular.
For example, we had a table called "REJECTS" on a db used by a rating process, containing the records rejected from one run of the program, and I don't see any reason in not using plural for that table (naming it "REJECT" would have been just funny, or too optimistic).
About the other problem (quotes) it depends on the SQL dialect. Oracle doesn't require quotes around table names.
As others have mentioned here, conventions should be a tool for adding to the ease of use and readability. Not as a shackle or a club to torture developers.
That said, my personal preference is to use singular names for both tables and columns. This probably comes from my programming background. Class names are generally singular unless they are some sort of collection. In my mind I am storing or reading individual records in the table in question, so singular makes sense to me.
This practice also allows me to reserve plural table names for those that store many-to-many relationships between my objects.
I try to avoid reserved words in my table and column names, as well. In the case in question here it makes more sense to go counter to the singular convention for Users to avoid the need to encapsulate a table that uses the reserved word of User.
I like using prefixes in a limited manner (tbl for table names, sp_ for proc names, etc), though many believe this adds clutter. I also prefer CamelBack names to underscores because I always end up hitting the + instead of _ when typing the name. Many others disagree.
Here is another good link for naming convention guidelines: http://www.xaprb.com/blog/2008/10/26/the-power-of-a-good-sql-naming-convention/
Remember that the most important factor in your convention is that it make sense to the people interacting with the database in question. There is no "One Ring to Rule Them All" when it comes to naming conventions.
We run similar standards, when scripting we demand [ ] around names, and where appropriate schema qualifiers - primarily it hedges your bets against future name grabs by the SQL syntax.
SELECT [Name] FROM [dbo].[Customer] WHERE [Location] = 'WA'
This has saved our souls in the past - some of our database systems have run 10+ years from SQL 6.0 through SQL 2005 - way past their intended lifespans.
I don't like plural table names because some nouns in English are not countable (water, soup, cash) or the meaning changes when you make it countable (chicken vs a chicken; meat vs bird). I also dislike using abbreviations for table name or column name because doing so adds extra slope to the already steep learning curve.
Ironically, I might make User an exception and call it Users because of USER (Transac-SQL), because I too don't like using brackets around tables if I don't have to.
I also like to name all the ID columns as Id, not ChickenId or ChickensId (what do plural guys do about this?).
All this is because I don't have proper respect for the database systems, I am just reapplying one-trick-pony knowledge from OO naming conventions like Java's out of habit and laziness. I wish there were better IDE support for complicated SQL.
Others have given pretty good answers as far as "standards" go, but I just wanted to add this... Is it possible that "User" (or "Users") is not actually a full description of the data held in the table? Not that you should get too crazy with table names and specificity, but perhaps something like "Widget_Users" (where "Widget" is the name of your application or website) would be more appropriate.
I solved the same problem by naming the table "Employee" (actually "Employees"). I try to stay as far away as possible from any conflict with possibly reserved words. Even "Users" is uncomfortably close for me.
If you use certain frameworks like Zend Framework (PHP) it is only wise to use plural for table classes and singular for row classes.
So say you create a table object $users = new Users() and have declared the row class to be User you will be able to call new User() as well.
Now if you use singular for table names you would have to do something like new UserTable() with the row being new UserRow(). This looks more clumsy to me than just having an object Users() for the table and User() objects for the rows.
If you go there will be trouble, but if you stay it will be double.
I'd much rather go against some supposed non-plurals naming convention than name my table after something which might be a reserved word.
The system tables/views of the server itself (SYSCAT.TABLES, dbo.sysindexes, ALL_TABLES, information_schema.columns, etc.) are almost always plural. I guess for the sake of consistency I'd follow their lead.
I also would go with plurals, and with the aforementioned Users dilema, we do take the square bracketing approach. We do this to provide uniformity between both database architecture and application architecture, with the underlying understanding that the Users table is a collection of User values as much as a Users collection in a code artifact is a collection of User objects. Having our data team and our developers speaking the same conceptual language (although not always the same object names) makes it easier to convey ideas between them.
In his book "SQL Programming Style," Joe Celko suggests that a collection (e.g. a table) should be named in the plural, while a scalar data element (e.g. a column) should be named in the singular.
He cites ISO-11179-4 as a standard for metadata naming, which supports this guideline.
If you use Object Relational Mapping tools or will in the future I suggest Singular.
Some tools like LLBLGen can automatically correct plural names like Users to User without changing the table name itself. Why does this matter? Because when it's mapped you want it to look like User.Name instead of Users.Name or worse from some of my old databases tables naming tblUsers.strName which is just confusing in code.
My new rule of thumb is to judge how it will look once it's been converted into an object.
one table I've found that does not fit the new naming I use is UsersInRoles. But there will always be those few exceptions and even in this case it looks fine as UsersInRoles.Username.
I stick with Singular for table names and any programming entity. The reason? The fact that there are irregular plurals in English like mouse --> mice and sheep --> sheep. Then, if I need a collection, i just use 'mouses' or 'sheeps', and move on. It really helps the plurality stand out, and I can easily and programatically determine what the collection of things would look like. So, my rule is : every thing is singular , every collection of things is singular with an 's' appended. Helps with ORMs too.
I am of the firm belief that in an Entity Relation Diagram, the entity should be reflected with a singular name, similar to a class name being singular. Once instantiated, the name reflects its instance. So with databases, the entity when made into a table (a collection of entities or records) is plural. Entity, User is made into table Users. I would agree with others who suggested maybe the name User could be improved to Employee or something more applicable to your scenario.
This then makes more sense in a SQL statement because you are selecting from a group of records and if the table name is singular, it doesn't read well.
Singular. I'd call an array containing a bunch of user row representation objects 'users', but the table is 'the user table'. Thinking of the table as being nothing but the set of the rows it contains is wrong, IMO; the table is the metadata, and the set of rows is hierarchically attached to the table, it is not the table itself.
I use ORMs all the time, of course, and it helps that ORM code written with plural table names looks stupid.
I am a fan of singular table names as they make my ER diagrams using CASE syntax easier to read, but by reading these responses I'm getting the feeling it never caught on very well? I personally love it. There is a good overview with examples of how readable your models can be when you use singular table names, add action verbs to your relationships and form good sentences for every relationships. It's all a bit of overkill for a 20 table database but if you have a DB with hundreds of tables and a complex design how will your developers ever understand it without a good readable diagram?
http://www.aisintl.com/case/method.html
As for prefixing tables and views I absolutely hate that practice. Give a person no information at all before giving them possibly bad information. Anyone browsing a db for objects can quite easily tell a table from a view, but if I have a table named tblUsers that for some reason I decide to restructure in the future into two tables, with a view unifying them to keep from breaking old code I now have a view named tblUsers. At this point I am left with two unappealing options, leave a view named with a tbl prefix which may confuse some developers, or force another layer, either middle tier or application to be rewritten to reference my new structure or name viewUsers. That negates a large part of the value of views IMHO.
I will just give my opinion why I use singular names.
For example, I need to get all the fields from an user:
SELECT * FROM user (SELECT EVERY FIELDS FROM USER.
I need the name of the user that is 21 years old:
SELECT * FROM user WHERE age = '21' (SELECT EVERY FIELDS FROM USER WHICH HAVE 21 YEARS OLD)
Of course the plural way can be used by the same means, but for my brain to read, I really think that's the right way to go.
How about this as a simple example:
SELECT Customer.Name, Customer.Address FROM Customer WHERE Customer.Name > "def"
vs.
SELECT Customers.Name, Customers.Address FROM Customers WHERE Customers.Name > "def"
The SQL in the latter is stranger sounding than the former.
I vote for singular.
IMHO, Table names should be plular like Customers.
Class names should be singular like Customer if it maps to a row in Customers table.
I always use singular table names but, as already stated, the most important thing is to be consequent and use the same form for all names.
What I don't like about plural table names is that combined names can get quite strange. If for example you have a table named Users and you want to store properties for the user, this would result in a table named UsersProperties...
Tables: plural
Multiple users are listed in the users table.
Models: singular
A singular user can be selected from the users table.
Controllers: plural
http://myapp.com/users would list multiple users.
That's my take on it anyway.
I think using the singular is what we were taught in university. But at the same time you could argue that unlike in object oriented programming, a table is not an instance of its records.
I think I'm tipping in favour of the singular at the moment because of plural irregularities in English. In German it's even worse due to no consistent plural forms - sometimes you cannot tell if a word is plural or not without the specifying article in front of it (der/die/das). And in Chinese languages there are no plural forms anyway.
I've actually always thought it was popular convention to use plural table names. Up until this point I've always used plural. I can understand the argument for singular table names, but to me plural makes more sense. A table name usually describes what the table contains. In a normalized database, each table contains specific sets of data. Each row is an entity and the table contains many entities. Thus the plural form for the table name. A table of cars would have the name "cars" and each row is a car. I'll admit that specifying the table along with the field in a table.field manner is the best practice and that having singular table names is more readable. However in the following two examples, the former makes more sense: SELECT * FROM cars WHERE color='blue'; SELECT * FROM car WHERE color='blue';
Honestly, I will be rethinking my position on the matter, and I would rely on the actual conventions used by the organization I'm developing for. However, I think for my personal conventions, I'll stick with plural table names. To me it makes more sense.
I prefer to use the uninflected noun, which in English happens to be singular.
Inflecting the number of the table name causes orthographic problems (as many of the other answers show), but choosing to do so because tables usually contain multiple rows is also semantically full of holes. This is more obvious if we consider a language that inflects nouns based on case (as most do):
Since we're usually doing something with the rows, why not put the name in the accusative case? If we have a table that we write to more than we read, why not put the name in dative? It's a table of something, why not use the genitive? We wouldn't do this, because the table is defined as an abstract container that exists regardless of it's state or usage. Inflecting the noun without a precise and absolute semantic reason is babbling.
Using the uninflected noun is simple, logical, regular and language-independent.
I've always used singular simply because that's the was I was taught. However, while creating a new schema recently, for the first time in a long time, I actively decided to maintain this convention simply because... it's shorter. Adding an 's' to the end of every table name seems as useless to me as adding 'tbl_' in front of every one.