Update target table using metadata and source tabl

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Update target table using metadata and source tabl

Author

Topic

flamblaster
Constraint Violating Yak Guru

384 Posts

Posted - 2013-10-04 : 21:30:12

Hey guys,

I'd like to figure out how to use the @FieldDescription table below as an intermediate table between the @SourceData and @Stops data. Any ideas?
declare @Stop table (StopId int, UserField varchar(20))
declare @FieldDescription table (Label varchar(10), ColumnName varchar(10))
declare @UpdateSource table (HasPathway varchar(10))

insert into @Stop (StopId, UserField)
values (1, 'Yes')

insert into @FieldDescription (Label, ColumnName)
values ('HasPathway', 'UserField')

insert into @UpdateSource (HasPathway)
values ('No')

I want to update @Stop.UserField with thevalue from @UpdateSource where @UpdateSource.HasPathway=@Stop.UserField...but I need to use the @FieldDescription table to determine how to map the columns.

khtan
In (Som, Ni, Yak)

17689 Posts

Posted - 2013-10-06 : 03:37:30

you will need to use Dynamic SQL

take a look at this http://www.sommarskog.se/dynamic_sql.html

KH
[spoiler]Time is always against us[/spoiler]

flamblaster
Constraint Violating Yak Guru

384 Posts

Posted - 2013-10-06 : 23:11:56

thanks Khtan,

I'm generating a script using information_schema.columns to update columns in the target table from the source. I'll try to wrap it up in dynamic sql. thanks for the tip!

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2013-10-07 : 05:40:33

[code]
SELECT *
FROM
(
SELECT m.StopId,m.Col,v.Val
FROM
(
SELECT StopId,Col,Val
FROM @stop s
UNPIVOT (Val FOR Col IN ([UserField],..any other columns you want))u
)m
JOIN @FieldDescription fd
ON fd.ColumnName = m.Col
JOIN (
SELECT Col,Val
FROM @UpdateSource u
UNPIVOT (Val FOR Col IN ([HasPathway],..any other columns you want))u
)n
ON n.Col = fd.Label
)t
PIVOT (MAX(Val) FOR Col IN (([UserField],..any other columns you want))p
[/code]

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