Databases
StackOverflow2013
Postsdbo
PODate range overlapping check constraint
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PODate range overlapping check constraint
    primarykey
    data
    text
    <p>I've a simple table in sql server 2005 with 3 columns: DateStart, DateEnd and Value. I tried to set a "table check constraint" to avoid inserting overlapping records. For instance if in such table there is a record with DateStart = 2012-01-01 (first January) and DateEnd 2012-01-15 (15th January) than Check constraint must avoid inserting a record with DateStart=2012-01-10 (no care DateEnd), a record with DateEnd=2012-01-10 (no care DateStart) or a record with DateStart 2011-12-10 and DateEnd 2012-02-01.</p> <p>I defined a UDF in such way:</p> <pre><code>CREATE FUNCTION [dbo].[ufn_checkOverlappingDateRange] ( @DateStart AS DATETIME ,@DateEnd AS DATETIME ) RETURNS BIT AS BEGIN DECLARE @retval BIT /* date range at least one day */ IF (DATEDIFF(day,@DateStart,@DateEnd) &lt; 1) BEGIN SET @retval=0 END ELSE BEGIN IF EXISTS ( SELECT * FROM [dbo].[myTable] WHERE ((DateStart &lt;= @DateStart) AND (DateEnd &gt; @DateStart)) OR ((@DateStart &lt;= DateStart) AND (@DateEnd &gt; DateStart)) ) BEGIN SET @retval=0 END ELSE BEGIN SET @retval=1 END END RETURN @retval END </code></pre> <p>Then thought check could be this:</p> <pre><code>ALTER TABLE [dbo].[myTable] WITH CHECK ADD CONSTRAINT [CK_OverlappingDateRange] CHECK ([dbo].[ufn_checkOverlappingDateRange]([DateStart],[DateEnd])&lt;&gt;(0)) </code></pre> <p>But even with [myTable] empty EXISTS Operator returns true when i insert first record. Where i'm wrog ? Is it possible to set a constraint like this ?</p> <p>BTW I consider DateStart includes in range and DateEnd excludes from range.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USAntonio Manello
    1. USAntonio Manello
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PODate range overlapping check constraint
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PODate range overlapping check constraint
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PODate range overlapping check constraint
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload