SQL Server

Serialize / Deserialize Hashtable to/from XML

Demonstrates how to seralize / deserialize a Hashtable to/from XML.

Note: This example requires Chilkat v9.5.0.64 or later.

SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- Note: This example requires Chilkat v9.5.0.64 or later.

    -- Add some entries to a hashtable.
    DECLARE @hashTab int
    EXEC @hr = sp_OACreate 'Chilkat.Hashtable', @hashTab OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int
    EXEC sp_OAMethod @hashTab, 'AddStr', @success OUT, 'aaa', '111'
    EXEC sp_OAMethod @hashTab, 'AddStr', @success OUT, 'bbb', '222'
    EXEC sp_OAMethod @hashTab, 'AddStr', @success OUT, 'ccc', '333'

    -- Serialize to XML
    DECLARE @sb int
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sb OUT

    EXEC sp_OAMethod @hashTab, 'ToXmlSb', @success OUT, @sb
    EXEC sp_OAMethod @sb, 'GetAsString', @sTmp0 OUT
    PRINT @sTmp0

    PRINT '---'

    -- The output is as follows.  Each hash table entry
    -- is contained in an "e" node.  The entry's key
    -- is in the "k" node, and the value in the "v" node.

    -- <?xml version="1.0" encoding="utf8-8"?>
    -- <hashtable>
    -- <e><k>aaa</k><v>111</v></e>
    -- <e><k>bbb</k><v>222</v></e>
    -- <e><k>ccc</k><v>333</v></e>
    -- </hashtable>
    -- 

    -- Now load (deserialize) into a new hash table.
    DECLARE @hashTab2 int
    EXEC @hr = sp_OACreate 'Chilkat.Hashtable', @hashTab2 OUT

    EXEC sp_OAMethod @hashTab2, 'AddFromXmlSb', @success OUT, @sb

    -- Get the hash table keys, and lookup each (to show 
    -- that the hash table was correctly deserialized).
    -- The GetKeys method can return the keys in any order.
    DECLARE @sTable int
    EXEC @hr = sp_OACreate 'Chilkat.StringTable', @sTable OUT

    EXEC sp_OAMethod @hashTab2, 'GetKeys', @success OUT, @sTable

    DECLARE @i int
    SELECT @i = 0
    DECLARE @numKeys int
    EXEC sp_OAGetProperty @sTable, 'Count', @numKeys OUT
    WHILE @i < @numKeys
      BEGIN
        DECLARE @key nvarchar(4000)
        EXEC sp_OAMethod @sTable, 'StringAt', @key OUT, @i

        EXEC sp_OAMethod @hashTab2, 'LookupStr', @sTmp0 OUT, @key
        PRINT @key + ': ' + @sTmp0
        SELECT @i = @i + 1
      END

    EXEC @hr = sp_OADestroy @hashTab
    EXEC @hr = sp_OADestroy @sb
    EXEC @hr = sp_OADestroy @hashTab2
    EXEC @hr = sp_OADestroy @sTable


END
GO