SQL Server

Check if Integer Exists at JSON Path

Demonstrates how to get an integer value at a JSON path, and how to check to see if it exists. 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
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @json int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @json OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- First build simple JSON..
    EXEC sp_OAMethod @json, 'UpdateInt', @success OUT, 'test.abc', 100

    EXEC sp_OASetProperty @json, 'EmitCompact', 0
    EXEC sp_OAMethod @json, 'Emit', @sTmp0 OUT
    PRINT @sTmp0

    -- This is our JSON:
    -- {
    --   "test": {
    --     "abc": 100,
    --   }
    -- }

    DECLARE @path nvarchar(4000)
    SELECT @path = 'test.notHere'

    -- The call to IntOf will return 0, because it's not present.
    -- But how do we know if it really was present, and the value was truly 0?
    DECLARE @val int
    EXEC sp_OAMethod @json, 'IntOf', @val OUT, @path

    PRINT 'val = ' + @val

    -- We cannot use LastMethodSuccess because LastMethodSuccess only applies
    -- to methods that:
    -- - return a string
    -- - return a new Chilkat object, binary bytes, or a date/time.
    -- - returns a boolean status where 1 = success and 0 = failed.
    -- - returns an integer where failure is defined by a return value less than zero.
    -- The IntOf method fits none of these requirements, and therefore the LastMethodSuccess 
    -- is not a valid indicator..
    DECLARE @wasFound int
    EXEC sp_OAGetProperty @json, 'LastMethodSuccess', @wasFound OUT


    PRINT 'wasFound = ' + @wasFound + ' (not a valid indicator)'

    -- Instead, if the returned value is 0, we can double-check to see if the member was truly there..
    IF @val = 0
      BEGIN
        EXEC sp_OAMethod @json, 'HasMember', @wasFound OUT, @path

        PRINT 'wasFound = ' + @wasFound
        IF @wasFound = 1
          BEGIN

            PRINT 'The value was present and is 0.'
          END
        ELSE
          BEGIN

            PRINT 'no member is present at test.notHere'
          END
      END
    ELSE
      BEGIN

        PRINT 'val = ' + @val
      END

    -- Alternatively, you could check to see if the member exists beforehand..
    EXEC sp_OAMethod @json, 'HasMember', @iTmp0 OUT, @path
    IF @iTmp0 = 1
      BEGIN

        EXEC sp_OAMethod @json, 'IntOf', @iTmp0 OUT, @path
        PRINT 'val = ' + @iTmp0
      END
    ELSE
      BEGIN

        PRINT 'no member at ' + @path
      END

    EXEC @hr = sp_OADestroy @json


END
GO