SQL Server

Loading and Parsing a JSON Array

See more JSON Examples

A JSON array is JSON that begins with "[" and ends with "]". For example, this is a JSON array that contains 3 JSON objects.

[{"name":"jack"},{"name":"john"},{"name":"joe"}]

A JSON object, however, is JSON that begins with "{" and ends with "}". For example, this JSON is an object that contains an array.

{"pets":[{"name":"jack"},{"name":"john"},{"name":"joe"}]}

This example shows how loading a JSON array is different than loading a JSON object. 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 @strJsonArray nvarchar(4000)
    SELECT @strJsonArray = '[{"name":"jack"},{"name":"john"},{"name":"joe"}]'

    DECLARE @strJsonObject nvarchar(4000)
    SELECT @strJsonObject = '{"pets":[{"name":"jack"},{"name":"john"},{"name":"joe"}]}'

    -- A JSON array must be loaded using JsonArray:
    DECLARE @jsonArray int
    EXEC @hr = sp_OACreate 'Chilkat.JsonArray', @jsonArray OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int
    EXEC sp_OAMethod @jsonArray, 'Load', @success OUT, @strJsonArray

    -- Examine the values:
    DECLARE @i int
    SELECT @i = 0
    EXEC sp_OAGetProperty @jsonArray, 'Size', @iTmp0 OUT
    WHILE @i < @iTmp0
      BEGIN
        DECLARE @jsonObj int
        EXEC sp_OAMethod @jsonArray, 'ObjectAt', @jsonObj OUT, @i

        EXEC sp_OAMethod @jsonObj, 'StringOf', @sTmp0 OUT, 'name'
        PRINT @i + ': ' + @sTmp0
        EXEC @hr = sp_OADestroy @jsonObj

        SELECT @i = @i + 1
      END

    -- Output is:

    -- 	0: jack
    -- 	1: john
    -- 	2: joe

    -- A JSON object must be loaded using JsonObject
    DECLARE @jsonObject int
    EXEC @hr = sp_OACreate 'Chilkat.JsonObject', @jsonObject OUT

    EXEC sp_OAMethod @jsonObject, 'Load', @success OUT, @strJsonObject

    -- Examine the values:
    SELECT @i = 0
    DECLARE @numPets int
    EXEC sp_OAMethod @jsonObject, 'SizeOfArray', @numPets OUT, 'pets'
    WHILE @i < @numPets
      BEGIN
        EXEC sp_OASetProperty @jsonObject, 'I', @i

        EXEC sp_OAMethod @jsonObject, 'StringOf', @sTmp0 OUT, 'pets[i].name'
        PRINT @i + ': ' + @sTmp0
        SELECT @i = @i + 1
      END

    -- Output is:

    -- 	0: jack
    -- 	1: john
    -- 	2: joe

    EXEC @hr = sp_OADestroy @jsonArray
    EXEC @hr = sp_OADestroy @jsonObject


END
GO