Dynamic Data Paging

,

I've search high and low on the Internet for good examples of Paging Data in an application. However, none of the Examples were clean enough, or worked for all situations. For example, there are no examples of Data Paging for Tables with Composite Keys.

This Script is able to page Data on any Table, using any Criteria, Sorting, or Grouping as well as handling Composite Keys auto-magically.

Please let me know if you improve upon this or find problems.

CREATE PROCEDURE dbo.spGetDataPage
(
@Table VarChar(128) = Null, 
@Columns VarChar(1000) = '*', 
@Criteria VarChar(2000) = Null,
@Group VarChar(2000) = Null,
@Sort VarChar(2000) = Null,
@PageNo Int = 1, 
@PageSize Int = 0, 
@GetTotals Bit = 0,
@TotalRecords Int = 0 Output, 
@TotalPages Decimal(10,2) = 0 Output
)
AS
-- Variables
Set NoCount On
Declare @AllRecords Bit, @GetDefaultSort Bit, @Criteria1 VarChar(8000), @Criteria2 VarChar(8000)
Declare @KeyColumn VarChar(8000), @PageNoStr VarChar(50), @PageSizeStr VarChar(50), @SkipRows VarChar(50)
Declare @Cursor Cursor, @Column VarChar(128), @Type VarChar(50), @MaxLen SmallInt

-- Set the Defaults
If (@PageNo < 1) Set @PageNo = 1
Select @KeyColumn = '', @Criteria1 = '', @Criteria2 = ''
Select @Criteria = Upper(@Criteria), @Sort = Upper(@Sort), @Group = Upper(@Group)
Select @Criteria = IsNull(@Criteria, ''), @Sort = IsNull(@Sort, ''), @Group = IsNull(@Group, '')
Select @PageNoStr = Convert(VarChar(50), @PageNo), @PageSizeStr = Convert(VarChar(50), @PageSize)
If (@Sort = '') Set @GetDefaultSort = 1

-- Determine the Key Columns from the Table
If (Select Count(*) From Information_Schema.Key_Column_Usage CU
Inner Join Information_Schema.Columns C ON (CU.Table_Name = C.Table_Name) And (CU.Column_Name = C.Column_Name)
Where (CU.Table_Name = @Table) And (CU.Constraint_Name IN(Select Name From SysObjects Where Xtype = 'pk'))) = 1
BEGIN
Select @KeyColumn = C.Column_Name 
From Information_Schema.Key_Column_Usage CU
Inner Join Information_Schema.Columns C ON (CU.Table_Name = C.Table_Name) And (CU.Column_Name = C.Column_Name)
Where (CU.Table_Name = @Table) And (CU.Constraint_Name IN(Select Name From SysObjects Where Xtype = 'pk'))
END
Else
BEGIN
Set @Cursor = Cursor Fast_Forward For
Select C.Column_Name As ColumnName, Data_Type As Type, IsNull(C.Character_Maximum_Length, C.Character_Octet_Length) As MaxLen
From Information_Schema.Key_Column_Usage CU
Inner Join Information_Schema.Columns C ON (CU.Table_Name = C.Table_Name) And (CU.Column_Name = C.Column_Name)
Where (CU.Table_Name = @Table) And (CU.Constraint_Name IN(Select Name From SysObjects Where Xtype = 'pk'))
Open @Cursor
Fetch Next From @Cursor Into @Column, @Type, @MaxLen
While (@@Fetch_Status <> -1)
BEGIN
If (@@Fetch_Status <> -2)
BEGIN
Set @KeyColumn = @KeyColumn + ' Convert(VarChar(50), ' + @Column + ') + '':'' +'
If (@GetDefaultSort = 1)
BEGIN
Set @Sort = @Sort + @Column + ', '
END
END
Fetch Next From @Cursor Into @Column, @Type, @MaxLen
END
Close @Cursor
DeAllocate @Cursor
Set @KeyColumn = SubString(@KeyColumn, 1, Len(@KeyColumn) - 7)
If (@GetDefaultSort = 1) Set @Sort = SubString(@Sort, 1, Len(@Sort) - 1)
END

-- Page Size
If (@PageSize Is Null) OR (@PageSize < 1)         -- Bring all records, don't do paging.
Set @AllRecords = 1
Else
BEGIN
Set @AllRecords = 0
    Set @SkipRows = Convert(VarChar(50), @PageSize * (@PageNo - 1))
END

-- Criteria
If (CharIndex('WHERE', @Criteria) > 0) Set @Criteria = Replace(@Criteria, 'WHERE', '')
If (@Criteria Is Not Null) AND (@Criteria <> '')
BEGIN
Set @Criteria1 = ' WHERE (' + @Criteria + ') '
Set @Criteria2 = ' AND (' + @Criteria + ') '
END

-- Sorting
If (@Sort Is Not Null) AND (@Sort <> '')
BEGIN
If (CharIndex('ORDER BY', @Sort) = 0) Set @Sort = ' ORDER BY ' + @Sort + ' '
END

-- Grouping
If (@Group Is Not Null) AND (@Group <> '')
BEGIN
If (CharIndex('GROUP BY', @Group) = 0) Set @Group = ' GROUP BY ' + @Group + ' '
END

-- Return the Records
If (@AllRecords = 1)                   -- Ignore paging and run a simple SELECT.
BEGIN
   EXEC ('Select ' + @Columns + ' From ' + @Table + ' ' + @Criteria1 + ' ' + @Group + ' ' + @Sort)
END
Else
BEGIN
If (@PageNo = 1)                                -- In this case we can execute a more efficient query with no subqueries.
BEGIN
EXEC (
'Select Top ' + @PageSizeStr + ' ' + @Columns + ' From ' + @Table + ' ' + @Criteria1 + ' ' + @Group + ' ' + @Sort
)
END
Else
BEGIN
EXEC (
'Select Top ' + @PageSizeStr + ' ' + @Columns + ' From ' + @Table
+ ' Where ' + @KeyColumn + ' NOT IN(Select Top ' + @SkipRows + ' ' + @KeyColumn + ' From ' + @Table + ' ' + @Criteria1 + ' ' + @Group + ' ' + @Sort + ')'
+ ' ' + @Criteria2 + ' ' + @Group + ' ' + @Sort
)
END
END

If (@GetTotals = 1)
BEGIN
Select @TotalRecords = Sum(Rows) From dbo.SysIndexes Where ID IN(Select ID From dbo.SysObjects Where Name = @Table)
If (@PageSize > 0) Set @TotalPages = Ceiling(@TotalRecords / @PageSize) + 1
END

RETURN

Rate

Share

Share

Rate