SQL Server 2008 - Default column value - should i use null or empty string? -


For some time I am arguing if I should leave the column which I do not know will pass the data and set The value for the empty string will be ('') or just allow zero.

I want to hear what is the recommended practice here.

If it makes a difference, then I am using it as a consumer application.

I'm scared that ...

It depends!

There is no single answer to this question.

As a sign in other reactions, at the level of SQL , NULL and very different words in the empty string , formerly indicating it That value is unknown, later it shows that the value is "invisible thing" (in display and report), but no "known value" is less. An example given in this context is the middle name. A zero value in the "middle_name" column will indicate that we do not know whether the name is or not between the underlying person, and if so what is this name, an empty string will indicate that we know that this person < No is a middle name.

This said, two other types of factors can help you choose between these options for the given column.

  • Li> Strong>
    For example it is important to know whether the empty string is a valid value for the underlying data. If this is the case, then we can clear the information if we also use empty string for "unknown information". Another idea is whether some alternative values ​​can be used in this case, when our There is no information for the nearest column;

    SQL Behavior and Utilities
    Considering SQL behavior, not using the choice of using or using, rather than 'n / a' Or 'unspecified' or 'TBD' are better values. Zero, space can be inspired by thought, by the desire to create a filtered index or by facilitating the COALESCE () function (which can be simulated with the case statement, but in more verbose fashion). Another idea is whether a query might try to query multiple columns to add them (like SELECT name + ',' + middle_name AS LongName etc.).

    String beyond the validity of the choice of zero versus empty, in the given position, try a general idea and be as consistent as possible, that is, try and stick in a special way, and only / deliberately / Clearly depart for good reasons and in some cases.


    • Comments

    Post a Comment

    Popular posts from this blog

    sql - dynamically varied number of conditions in the 'where' statement using LINQ -

    I am using my first project LINQ (in mvc), so maybe there's something very simple that I remember. However, a day of searching and experimenting does not work, so it works. I am trying to write a LINQ query (Linux to SQL) in which in many cases where the statement is different from an OR or an AND. We do not know how many conditions are going in the query till runtime. This search is for filter control, where the user can choose multiple criteria for filtering. Select from table where table.col = 1 or table.col = 2 or table.col = 7 .... 'Other number of conditions Before I just create the SQL query as a string, while looping over all the situations. However, it seems that there should be a good way to do this in LINQ. I tried to use Expression trees, but they had a second thought for this moment on my head, where the lambda function was to be executed inside the statement such as: values ​​for matchingRows = matchingRows for each value Where (function (row) row.c...
    Read more

    asp.net mvc - Dynamically Generated Ajax.BeginForm -

    I have a problem with ASP.NET MVC Ajax forms. I generate many Ajax form in a table such as: & Lt; Input type = "submit" name = "activity" value = "add activity" / & gt; & Lt;%}% & gt; & Lt; / TD & gt; & Lt; / TR & gt; & Lt;%}% & gt; So far so good. When I post one of those forms, it gives a partial view in a div, and in this new partial view a new Ajax Beginnform (which is not in Genesis form) This second Ajax Beginnorf is exactly like the ones I got on the table, but when I post it, I do not get the "Ajax Post", but a normal post that sends me to a new page, I do not know whether the two Ajax forms What is the reason for the difference between, why is it the "dynamically generated" Ajax form behaves like a normal HTML form? By the way, I know that I can do it in different ways using javascript, but I would like to understand whether it can only be done using MVC helplars and Ajax lib...
    Read more

    Debug on symbian -

    I am using trk for phone debug This works well for the Holorld project But when I start the project in phone debug mode 1) the load failed 2) TrkProtocolPlugin: to target the specified file Failure (please verify If any body understands what problem I am experiencing, then this problem helps me Pre-release If the application has the privileges assigned (with the appropriate certificate) itemprop = "text" > In your case, I will check: / li> If there is no conflict of application ID with any other application of device If there are problematic commands in the installation package (for example copy copy for non-accessible directories)
    Read more