Advanced group design

  • Hi All

    I ask you guidance on this design question because this seems to be one of those things where if you don't get it right and it gets implemented much suffering will follow...

    I need to design some advanced group functionality. I am calling the three functions I need 'group of groups' and 'group minus group' and 'groups plus manual'

    Given the group 'Blue and Yellow'. Clearly I can add all the individual blue and yellow stars to this group but I would like to define the 'Blue and Yellow' group as being comprised of the two groups: Bluestars and Yellowstars.

    Given the group '10 Brightest No Supergiants'. I would like to define this as being composed of the members of the group '10 Brightest' minus the group 'Supergiants'.

    The group 'Blue stars and my current favorite star' should be composed of the group Bluestars and one other star manually selected.

    Any design ideas would be much appreciated.

    CREATE TABLE #Stars (Star varchar(30))

    INSERT INTO #Stars (Star) VALUES ('Sirius')

    INSERT INTO #Stars (Star) VALUES ('Canopus')

    INSERT INTO #Stars (Star) VALUES ('Rigil Kentaurus')

    INSERT INTO #Stars (Star) VALUES ('Arcturus')

    INSERT INTO #Stars (Star) VALUES ('Vega')

    INSERT INTO #Stars (Star) VALUES ('Capella')

    INSERT INTO #Stars (Star) VALUES ('Rigel')

    INSERT INTO #Stars (Star) VALUES ('Procyon')

    INSERT INTO #Stars (Star) VALUES ('Achernar')

    INSERT INTO #Stars (Star) VALUES ('Betelgeuse')

    CREATE TABLE #StarGroups (StarGroup varchar(45))

    INSERT INTO #StarGroups (StarGroup) VALUES ('10 Brightest')

    INSERT INTO #StarGroups (StarGroup) VALUES ('Supergiants')

    INSERT INTO #StarGroups (StarGroup) VALUES ('Bluestars')

    INSERT INTO #StarGroups (StarGroup) VALUES ('Yellowstars')

    INSERT INTO #StarGroups (StarGroup) VALUES ('10 Brightest No Supergiants')

    INSERT INTO #StarGroups (StarGroup) VALUES ('Blue and Yellow')

    INSERT INTO #StarGroups (StarGroup) VALUES ('Blue stars and my current favorite star')

    CREATE TABLE #StarGroupMembers (StarGroup varchar(15),Star varchar(30))

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Sirius')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Canopus')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Rigil Kentaurus')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Arcturus')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Vega')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Capella')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Rigel')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Procyon')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Achernar')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('10 Brightest','Betelgeuse')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Supergiants','Rigel')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Supergiants','Achernar')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Supergiants','Betelgeuse')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Bluestars','Rigel')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Yellowstars','Procyon')

    INSERT INTO #StarGroupMembers (StarGroup,Star) VALUES ('Yellowstars','Capella')

    SELECT * FROM #Stars

    SELECT * FROM #StarGroups

    SELECT * FROM #StarGroupMembers

    DROP TABLE #Stars

    DROP TABLE #StarGroups

    DROP TABLE #StarGroupMembers

  • A lot depends on how frequently new groups are defined, how frequently group definitions change (whether by adding new members or removing existing members or adding new subgroups or removing existing subgroups), and how deeply nested are your groups. I imagine the nesting depth will be fairly small, so it's fairly easy to design a structure in which it is easy to update group membership and to introduce new groups, and easy to provide the three functions you mention.

    Since groups are potentially very large (there are a lot of red stars, for example) and since a star can be a member of many groups, it's probably a good idea to use something shorter than names to make links within the data structure (but this, of course, should be made invisible to users). That just needs a table for each star/group which uses its name and provides its identifier, perhaps as a bigint (I can't remember whether there are enough stars to need that) which can be automatically generated

    You will need an additional table in addition to those in the code you posted to represent the subgroup relationship.

    It is then straightforward to build total group membership from subgroups and individual members using a recursive CTE, and creating groups which are built from other groups, with or without additional individually specified elemets, becomes trivial. Subtraction is trivial too.

    Tom

  • Thank for for your response. I was using Stars as sample data, my actual data is much more mundane.

    I expect my groups to contain at most 100 hundred members and the updates to be infrequent, perhaps dozens a month.

    I have a new design below. I have not written a way to select group members from this structure but I expect that would be fairly easy.

    Please freely critique this new structure.

    You mention an additional table. What could that structure look like? Would that allow for nested subgroups?

    CREATE TABLE Stars (Star varchar(30))

    INSERT INTO Stars (Star) VALUES ('Sirius')

    INSERT INTO Stars (Star) VALUES ('Canopus')

    INSERT INTO Stars (Star) VALUES ('Rigil Kentaurus')

    INSERT INTO Stars (Star) VALUES ('Arcturus')

    INSERT INTO Stars (Star) VALUES ('Vega')

    INSERT INTO Stars (Star) VALUES ('Capella')

    INSERT INTO Stars (Star) VALUES ('Rigel')

    INSERT INTO Stars (Star) VALUES ('Procyon')

    INSERT INTO Stars (Star) VALUES ('Achernar')

    INSERT INTO Stars (Star) VALUES ('Betelgeuse')

    CREATE TABLE StarGroups (StarGroup varchar(45))

    INSERT INTO StarGroups (StarGroup) VALUES ('10 Brightest')

    INSERT INTO StarGroups (StarGroup) VALUES ('Supergiants')

    INSERT INTO StarGroups (StarGroup) VALUES ('Bluestars')

    INSERT INTO StarGroups (StarGroup) VALUES ('Yellowstars')

    INSERT INTO StarGroups (StarGroup) VALUES ('10 Brightest No Supergiants')

    INSERT INTO StarGroups (StarGroup) VALUES ('Blue and Yellow')

    INSERT INTO StarGroups (StarGroup) VALUES ('Blue stars and my current favorite star')

    CREATE TABLE StarGroupMembers (StarGroup varchar(50),Member varchar(30),MemberType varchar(30))

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Sirius','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Canopus','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Rigil Kentaurus','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Arcturus','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Vega','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Capella','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Rigel','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Procyon','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Achernar','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest','Betelgeuse','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Supergiants','Rigel','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Supergiants','Achernar','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Supergiants','Betelgeuse','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Bluestars','Rigel','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Yellowstars','Procyon','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Yellowstars','Capella','Star')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Blue and Yellow','Bluestars','GroupAdd')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Blue and Yellow','Yellowstars','GroupAdd')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest No Supergiants','10 Brightest','GroupAdd')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('10 Brightest No Supergiants','Supergiants','GroupSubtract')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Blue stars and my current favorite star','Bluestars','GroupAdd')

    INSERT INTO StarGroupMembers (StarGroup,Member,MemberType) VALUES ('Blue stars and my current favorite sta','Procyon','Star')

    SELECT * FROM Stars

    SELECT * FROM StarGroups

    SELECT * FROM StarGroupMembers

    DROP TABLE Stars

    DROP TABLE StarGroups

    DROP TABLE StarGroupMembers

  • Revised DDL/DML.

    The data structure seems reasonable but I don't have an additional table that Tom suggested I may need.

    My initial attempt to write a select statement to solve a group compromised of one group minus a second group has failed miserably.

    I will struggle on. Comments and suggestions are certainly welcome.

    --Create Groups table

    CREATE TABLE [dbo].[Groups](

    [GroupCode] [varchar](12) NOT NULL,

    [GroupName] [varchar](40) NULL,

    [GroupType] [varchar](12) NOT NULL,

    [GroupDescription] [varchar](240) NULL,

    CONSTRAINT [PK_Groups] PRIMARY KEY CLUSTERED

    (

    [GroupCode] ASC

    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

    ) ON [PRIMARY]

    --Create GroupMembers table

    CREATE TABLE [dbo].[GroupMembers](

    [GroupCode] [varchar](12) NOT NULL,

    [Member] [varchar](50) NOT NULL,

    [MemberType] [varchar](12) NOT NULL,

    CONSTRAINT [PK_GroupMembers] PRIMARY KEY CLUSTERED

    (

    [GroupCode] ASC,

    [Member] ASC,

    [MemberType] ASC

    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

    ) ON [PRIMARY]

    GO

    ALTER TABLE [dbo].[GroupMembers] WITH CHECK ADD CONSTRAINT [FK_GroupMembers_Groups] FOREIGN KEY([GroupCode])

    REFERENCES [dbo].[Groups] ([GroupCode])

    GO

    ALTER TABLE [dbo].[GroupMembers] CHECK CONSTRAINT [FK_GroupMembers_Groups]

    GO

    ALTER TABLE [dbo].[GroupMembers] WITH NOCHECK ADD CONSTRAINT [CK_GroupMembers_MemberType] CHECK (([MemberType]='GroupDelete' OR [MemberType]='GroupAdd' OR [MemberType]='Delete' OR [MemberType]='Add'))

    GO

    ALTER TABLE [dbo].[GroupMembers] CHECK CONSTRAINT [CK_GroupMembers_MemberType]

    GO

    --Create Stars table

    CREATE TABLE [dbo].[Stars](

    [Star] [varchar](30) NOT NULL,

    CONSTRAINT [PK_Stars] PRIMARY KEY CLUSTERED

    (

    [Star] ASC

    )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

    ) ON [PRIMARY]

    --Populate sample data into stars table

    INSERT INTO Stars (Star) VALUES ('Sirius')

    INSERT INTO Stars (Star) VALUES ('Canopus')

    INSERT INTO Stars (Star) VALUES ('Rigil Kentaurus')

    INSERT INTO Stars (Star) VALUES ('Arcturus')

    INSERT INTO Stars (Star) VALUES ('Vega')

    INSERT INTO Stars (Star) VALUES ('Capella')

    INSERT INTO Stars (Star) VALUES ('Rigel')

    INSERT INTO Stars (Star) VALUES ('Procyon')

    INSERT INTO Stars (Star) VALUES ('Achernar')

    INSERT INTO Stars (Star) VALUES ('Betelgeuse')

    --Insert groups

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('10B','10 Brightest','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('SG','Supergiants','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('BS','Bluestars','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('YS','Yellowstars','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('10BNSG','10 Brightest No Supergiants','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('BYS','Blue and Yellow','Star',NULL)

    INSERT INTO Groups (GroupCode,Groupname,GroupType,GroupDescription) VALUES ('BSFAVE','Blue stars and my favorite star','Star',NULL)

    --Insert groups members

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Sirius','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Canopus','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Rigil Kentaurus','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Arcturus','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Vega','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Capella','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Rigel','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Procyon','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Achernar','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10B','Betelgeuse','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('SG','Rigel','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('SG','Achernar','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('SG','Betelgeuse','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('BS','Rigel','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('YS','Procyon','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('YS','Capella','Add')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10BNSG','10B','GroupAdd')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('10BNSG','Supergiants','GroupDelete')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('BYS','BS','GroupAdd')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('BYS','YS','GroupDelete')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('BSFAVE','BS','GroupAdd')

    INSERT INTO GroupMembers (GroupCode,Member,MemberType) VALUES ('BSFAVE','Procyon','Add')

    DECLARE @GroupCode [varchar](12)

    --SET @GroupCode= 'BSFAVE'

    --SET @GroupCode= '10B'

    SET @GroupCode= '10BNSG'

    --SET @GroupCode= 'BS'

    --SET @GroupCode= 'BYS'

    --SET @GroupCode= 'SG'

    --SET @GroupCode= 'YS'

    SELECT

    @GroupCode,

    GroupCode,

    Member

    FROM GroupMembers

    WHERE

    GroupCode IN

    (

    SELECT

    Member

    FROM GroupMembers GM

    WHERE

    GM.GroupCode = @GroupCode AND

    MemberType = 'GroupAdd'

    )

    /*

    AND GroupCode NOT IN

    (

    SELECT

    GroupCode

    FROM GroupMembers

    WHERE

    GroupCode IN

    (

    SELECT

    Member

    FROM GroupMembers GM

    WHERE

    GM.GroupCode = '10BNSG' AND

    MemberType = 'GroupAdd'

    )

    )

    */

    --SELECT * FROM Stars

    --SELECT * FROM Groups

    SELECT * FROM GroupMembers WHERE GroupCode = @GroupCode

    DROP TABLE GroupMembers

    DROP TABLE Groups

    DROP TABLE Stars

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