Well usually companies have their own view on seniority, and it could include how many years you have been there, but for what its worth for me a senior developer is a person who has experience with all stages of application development, which should imply that she/he can:
- design and understand client/server architecture,
- write code using best practices that is clean and maintainable,
- knows database design and programming
- understands design patterns and knows how to not abuse them,
- knows how to deploy application and has experience with CI.
- knows how to write proper unit test.
To sum it up I will use .NET as an example, in my eyes when someone says I am a senior .NET developer I assume that she/he has:
- used UMLs,
- knows how to write proper OOP and understands SOLID,
- can use MS SQL and some kind of ORM,
- uses some of the testing frameworks (e.g. NUnit),
- knows how to deploy application whether on IIS, or install it with ClickOnce for example.
- know how to handle source versioning (TFS or whatever is your poison)
I probably missed a few things, but that's about it for me. If a senor doesn't have these skills I assume first that she/he has great knowledge of company business which would make her/him a valuable asset, or that she/he got lucky, or it's a crappy company :)
And, Flying Spaghetti Monster be praised, know enough that designing a convoluted OOP hierarchy and diagramming out forests worth of UML diagrams is a terrible, terrible decision.
UML is pretty straight forward, and I rarely saw it being used in companies because of many reasons (spaghetti monster being the one :D), but I mentioned it because I'd expect that one showed now how to read them, since you will find them in literature (if you read any book on design patterns they are there).
To sum it up I will use .NET as an example, in my eyes when someone says I am a senior .NET developer I assume that she/he has: - used UMLs, - knows how to write proper OOP and understands SOLID, - can use MS SQL and some kind of ORM, - uses some of the testing frameworks (e.g. NUnit), - knows how to deploy application whether on IIS, or install it with ClickOnce for example. - know how to handle source versioning (TFS or whatever is your poison)
I probably missed a few things, but that's about it for me. If a senor doesn't have these skills I assume first that she/he has great knowledge of company business which would make her/him a valuable asset, or that she/he got lucky, or it's a crappy company :)