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Consuming JSON Strings in SQL Server
IF OBJECT_ID (N'dbo.parseJSON') IS NOT NULL
DROP FUNCTION dbo.parseJSON
GO
IF OBJECT_ID (N'dbo.ParseXML') IS NOT NULL
DROP FUNCTION dbo.ParseXML
GO
IF OBJECT_ID (N'dbo.ToJSON') IS NOT NULL
DROP FUNCTION dbo.ToJSON
GO
IF OBJECT_ID (N'dbo.ToXML') IS NOT NULL
DROP FUNCTION dbo.ToXML
GO
IF OBJECT_ID (N'dbo.JSONEscaped') IS NOT NULL
DROP FUNCTION dbo.JSONEscaped
GO
IF EXISTS (SELECT * FROM sys.types WHERE name LIKE 'Hierarchy')
DROP TYPE dbo.Hierarchy
go
CREATE TYPE dbo.Hierarchy AS TABLE
/*Markup languages such as JSON and XML all represent object data as hierarchies. Although it looks very different to the entity-relational model, it isn't. It is rather more a different perspective on the same model. The first trick is to represent it as a Adjacency list hierarchy in a table, and then use the contents of this table to update the database. This Adjacency list is really the Database equivalent of any of the nested data structures that are used for the interchange of serialized information with the application, and can be used to create XML, OSX Property lists, Python nested structures or YAML as easily as JSON.
Adjacency list tables have the same structure whatever the data in them. This means that you can define a single Table-Valued Type and pass data structures around between stored procedures. However, they are best held at arms-length from the data, since they are not relational tables, but something more like the dreaded EAV (Entity-Attribute-Value) tables. Converting the data from its Hierarchical table form will be different for each application, but is easy with a CTE. You can, alternatively, convert the hierarchical table into XML and interrogate that with XQuery
*/
(
element_id INT primary key, /* internal surrogate primary key gives the order of parsing and the list order */
sequenceNo [int] NULL, /* the place in the sequence for the element */
parent_ID INT,/* if the element has a parent then it is in this column. The document is the ultimate parent, so you can get the structure from recursing from the document */
Object_ID INT,/* each list or object has an object id. This ties all elements to a parent. Lists are treated as objects here */
NAME NVARCHAR(2000),/* the name of the object, null if it hasn't got one */
StringValue NVARCHAR(MAX) NOT NULL,/*the string representation of the value of the element. */
ValueType VARCHAR(10) NOT null /* the declared type of the value represented as a string in StringValue*/
)
go
CREATE FUNCTION dbo.JSONEscaped ( /* this is a simple utility function that takes a SQL String with all its clobber and outputs it as a sting with all the JSON escape sequences in it.*/
@Unescaped NVARCHAR(MAX) --a string with maybe characters that will break json
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
SELECT @Unescaped = REPLACE(@Unescaped, FROMString, TOString)
FROM (SELECT
'\"' AS FromString, '"' AS ToString
UNION ALL SELECT '\', '\\'
UNION ALL SELECT '/', '\/'
UNION ALL SELECT CHAR(08),'\b'
UNION ALL SELECT CHAR(12),'\f'
UNION ALL SELECT CHAR(10),'\n'
UNION ALL SELECT CHAR(13),'\r'
UNION ALL SELECT CHAR(09),'\t'
) substitutions
RETURN @Unescaped
END
GO
CREATE FUNCTION ToJSON
(
@Hierarchy Hierarchy READONLY
)
/*
the function that takes a Hierarchy table and converts it to a JSON string
Author: Phil Factor
Revision: 1.5
date: 1 May 2014
why: Added a fix to add a name for a list.
example:
Declare @XMLSample XML
Select @XMLSample='
<glossary><title>example glossary</title>
<GlossDiv><title>S</title>
<GlossList>
<GlossEntry ID="SGML" SortAs="SGML">
<GlossTerm>Standard Generalized Markup Language</GlossTerm>
<Acronym>SGML</Acronym>
<Abbrev>ISO 8879:1986</Abbrev>
<GlossDef>
<para>A meta-markup language, used to create markup languages such as DocBook.</para>
<GlossSeeAlso OtherTerm="GML" />
<GlossSeeAlso OtherTerm="XML" />
</GlossDef>
<GlossSee OtherTerm="markup" />
</GlossEntry>
</GlossList>
</GlossDiv>
</glossary>'
DECLARE @MyHierarchy Hierarchy -- to pass the hierarchy table around
insert into @MyHierarchy select * from dbo.ParseXML(@XMLSample)
SELECT dbo.ToJSON(@MyHierarchy)
*/
RETURNS NVARCHAR(MAX)--JSON documents are always unicode.
AS
BEGIN
DECLARE
@JSON NVARCHAR(MAX),
@NewJSON NVARCHAR(MAX),
@Where INT,
@ANumber INT,
@notNumber INT,
@indent INT,
@ii int,
@CrLf CHAR(2)--just a simple utility to save typing!
--firstly get the root token into place
SELECT @CrLf=CHAR(13)+CHAR(10),--just CHAR(10) in UNIX
@JSON = CASE ValueType WHEN 'array' THEN
+COALESCE('{'+@CrLf+' "'+NAME+'" : ','')+'['
ELSE '{' END
+@CrLf
+ case when ValueType='array' and NAME is not null then ' ' else '' end
+ '@Object'+CONVERT(VARCHAR(5),OBJECT_ID)
+@CrLf+CASE ValueType WHEN 'array' THEN
case when NAME is null then ']' else ' ]'+@CrLf+'}'+@CrLf end
ELSE '}' END
FROM @Hierarchy
WHERE parent_id IS NULL AND valueType IN ('object','document','array') --get the root element
/* now we simply iterat from the root token growing each branch and leaf in each iteration. This won't be enormously quick, but it is simple to do. All values, or name/value pairs withing a structure can be created in one SQL Statement*/
Select @ii=1000
WHILE @ii>0
begin
SELECT @where= PATINDEX('%[^[a-zA-Z0-9]@Object%',@json)--find NEXT token
if @where=0 BREAK
/* this is slightly painful. we get the indent of the object we've found by looking backwards up the string */
SET @indent=CHARINDEX(char(10)+char(13),Reverse(LEFT(@json,@where))+char(10)+char(13))-1
SET @NotNumber= PATINDEX('%[^0-9]%', RIGHT(@json,LEN(@JSON+'|')-@Where-8)+' ')--find NEXT token
SET @NewJSON=NULL --this contains the structure in its JSON form
SELECT
@NewJSON=COALESCE(@NewJSON+','+@CrLf+SPACE(@indent),'')
+case when parent.ValueType='array' then '' else COALESCE('"'+TheRow.NAME+'" : ','') end
+CASE TheRow.valuetype
WHEN 'array' THEN ' ['+@CrLf+SPACE(@indent+2)
+'@Object'+CONVERT(VARCHAR(5),TheRow.[OBJECT_ID])+@CrLf+SPACE(@indent+2)+']'
WHEN 'object' then ' {'+@CrLf+SPACE(@indent+2)
+'@Object'+CONVERT(VARCHAR(5),TheRow.[OBJECT_ID])+@CrLf+SPACE(@indent+2)+'}'
WHEN 'string' THEN '"'+dbo.JSONEscaped(TheRow.StringValue)+'"'
ELSE TheRow.StringValue
END
FROM @Hierarchy TheRow
inner join @hierarchy Parent
on parent.element_ID=TheRow.parent_ID
WHERE TheRow.parent_id= SUBSTRING(@JSON,@where+8, @Notnumber-1)
/* basically, we just lookup the structure based on the ID that is appended to the @Object token. Simple eh? */
--now we replace the token with the structure, maybe with more tokens in it.
Select @JSON=STUFF (@JSON, @where+1, 8+@NotNumber-1, @NewJSON),@ii=@ii-1
end
return @JSON
end
go
CREATE FUNCTION dbo.ParseXML( @XML_Result XML)
/*
Returns a hierarchy table from an XML document.
Author: Phil Factor
Revision: 1.2
date: 1 May 2014
example:
DECLARE @MyHierarchy Hierarchy
INSERT INTO @myHierarchy
select * from dbo.ParseXML((Select * from adventureworks.person.contact where contactID in (123,124,125) FOR XML path('contact'), root('contacts')))
SELECT dbo.ToJSON(@MyHierarchy)
DECLARE @MyHierarchy Hierarchy
INSERT INTO @myHierarchy
select * from dbo.ParseXML('<root><CSV><item Year="1997" Make="Ford" Model="E350" Description="ac, abs, moon" Price="3000.00" /><item Year="1999" Make="Chevy" Model="Venture "Extended Edition"" Description="" Price="4900.00" /><item Year="1999" Make="Chevy" Model="Venture "Extended Edition, Very Large"" Description="" Price="5000.00" /><item Year="1996" Make="Jeep" Model="Grand Cherokee" Description="MUST SELL!
air, moon roof, loaded" Price="4799.00" /></CSV></root>')
SELECT dbo.ToJSON(@MyHierarchy)
*/
RETURNS @Hierarchy TABLE
(
Element_ID INT PRIMARY KEY, /* internal surrogate primary key gives the order of parsing and the list order */
SequenceNo INT NULL, /* the sequence number in a list */
Parent_ID INT,/* if the element has a parent then it is in this column. The document is the ultimate parent, so you can get the structure from recursing from the document */
[Object_ID] INT,/* each list or object has an object id. This ties all elements to a parent. Lists are treated as objects here */
[Name] NVARCHAR(2000),/* the name of the object */
StringValue NVARCHAR(MAX) NOT NULL,/*the string representation of the value of the element. */
ValueType VARCHAR(10) NOT NULL /* the declared type of the value represented as a string in StringValue*/
)
AS
BEGIN
DECLARE @Insertions TABLE(
Element_ID INT IDENTITY PRIMARY KEY,
SequenceNo INT,
TheLevel INT,
Parent_ID INT,
[Object_ID] INT,
[Name] VARCHAR(50),
StringValue VARCHAR(MAX),
ValueType VARCHAR(10),
TheNextLevel XML,
ThisLevel XML)
DECLARE @RowCount INT, @ii INT
--get the
INSERT INTO @Insertions (TheLevel, Parent_ID, [Object_ID], [Name], StringValue, SequenceNo, TheNextLevel, ThisLevel)
SELECT 1 AS TheLevel, NULL AS Parent_ID, NULL AS [Object_ID],
FirstLevel.value('local-name(.)', 'varchar(255)') AS [Name], --the name of the element
FirstLevel.value('text()[1]','varchar(max)') AS StringValue,-- its value as a string
ROW_NUMBER() OVER(ORDER BY (SELECT 1)) AS SequenceNo,--the 'child number' (simple number here)
FirstLevel.query('*'), --The 'inner XML' of the current child
FirstLevel.query('.') --the XML of the parent
FROM @XML_Result.nodes('/*') a(FirstLevel) --get all nodes from the XML
SELECT @RowCount=@@RowCount
SELECT @ii=2
WHILE @RowCount>0 --while loop to avoid recursion.
BEGIN
INSERT INTO @Insertions (TheLevel, Parent_ID, [Object_ID], [Name], StringValue, SequenceNo, TheNextLevel, ThisLevel)
SELECT --all the elements first
@ii AS TheLevel,
a.Element_ID,
NULL,
[then].value('local-name(.)', 'varchar(255)'),
[then].value('text()[1]','varchar(max)'),
ROW_NUMBER() OVER(PARTITION BY a.Element_ID ORDER BY (SELECT 1)),
[then].query('*'),
[then].query('.')
FROM @Insertions a
CROSS apply a.TheNextLevel.nodes('*') whatsNext([then])
WHERE a.TheLevel = @ii - 1
UNION ALL -- to pick out the attributes of the preceding level
SELECT @ii AS TheLevel,
a.Element_ID,
NULL,
[then].value('local-name(.)', 'varchar(255)') AS [name],
[then].value('.','varchar(max)') AS [value],
ROW_NUMBER() OVER(PARTITION BY a.Element_ID
ORDER BY (
SELECT 1)),
'' , ''
FROM @Insertions a
CROSS apply a.ThisLevel.nodes('/*/@*') whatsNext([then])
WHERE a.TheLevel = @ii - 1 OPTION (RECOMPILE)
SELECT @RowCount=@@ROWCOUNT
SELECT @ii=@ii+1
END;
--roughly type the datatypes (no XSD available here)
UPDATE @Insertions SET
[Object_ID]=CASE WHEN StringValue IS NULL THEN Element_ID
ELSE NULL END,
ValueType = CASE
WHEN StringValue IS NULL THEN 'object'
WHEN LEN(StringValue)=0 THEN 'string'
WHEN StringValue LIKE '%[^0-9.-]%' THEN 'string'
WHEN StringValue LIKE '[0-9]' THEN 'int'
WHEN RIGHT(StringValue, LEN(StringValue)-1) LIKE'%[^0-9.]%' THEN 'string'
WHEN StringValue LIKE'%[0-9][.][0-9]%' THEN 'real'
WHEN StringValue LIKE '%[^0-9]%' THEN 'string'
ELSE 'int' END--and find the arrays
UPDATE @Insertions SET
ValueType='array'
WHERE Element_ID IN(
SELECT candidates.Parent_ID
FROM
(
SELECT Parent_ID, COUNT(*) AS SameName
FROM @Insertions
GROUP BY [Name],Parent_ID
HAVING COUNT(*)>1) candidates
INNER JOIN @Insertions insertions
ON candidates.Parent_ID= insertions.Parent_ID
GROUP BY candidates.Parent_ID
HAVING COUNT(*)=MIN(SameName))
INSERT INTO @Hierarchy (Element_ID,SequenceNo, Parent_ID, [Object_ID], [Name], StringValue,ValueType)
SELECT Element_ID, SequenceNo, Parent_ID, [Object_ID], [Name], COALESCE(StringValue,''), ValueType
FROM @Insertions
RETURN
END
GO
CREATE FUNCTION dbo.parseJSON( @JSON NVARCHAR(MAX))
RETURNS @hierarchy TABLE
(
element_id INT IDENTITY(1, 1) NOT NULL, /* internal surrogate primary key gives the order of parsing and the list order */
sequenceNo [int] NULL, /* the place in the sequence for the element */
parent_ID INT,/* if the element has a parent then it is in this column. The document is the ultimate parent, so you can get the structure from recursing from the document */
Object_ID INT,/* each list or object has an object id. This ties all elements to a parent. Lists are treated as objects here */
NAME NVARCHAR(2000),/* the name of the object */
StringValue NVARCHAR(MAX) NOT NULL,/*the string representation of the value of the element. */
ValueType VARCHAR(10) NOT null /* the declared type of the value represented as a string in StringValue*/
)
AS
BEGIN
DECLARE
@FirstObject INT, --the index of the first open bracket found in the JSON string
@OpenDelimiter INT,--the index of the next open bracket found in the JSON string
@NextOpenDelimiter INT,--the index of subsequent open bracket found in the JSON string
@NextCloseDelimiter INT,--the index of subsequent close bracket found in the JSON string
@Type NVARCHAR(10),--whether it denotes an object or an array
@NextCloseDelimiterChar CHAR(1),--either a '}' or a ']'
@Contents NVARCHAR(MAX), --the unparsed contents of the bracketed expression
@Start INT, --index of the start of the token that you are parsing
@end INT,--index of the end of the token that you are parsing
@param INT,--the parameter at the end of the next Object/Array token
@EndOfName INT,--the index of the start of the parameter at end of Object/Array token
@token NVARCHAR(200),--either a string or object
@value NVARCHAR(MAX), -- the value as a string
@SequenceNo int, -- the sequence number within a list
@name NVARCHAR(200), --the name as a string
@parent_ID INT,--the next parent ID to allocate
@lenJSON INT,--the current length of the JSON String
@characters NCHAR(36),--used to convert hex to decimal
@result BIGINT,--the value of the hex symbol being parsed
@index SMALLINT,--used for parsing the hex value
@Escape INT --the index of the next escape character
DECLARE @Strings TABLE /* in this temporary table we keep all strings, even the names of the elements, since they are 'escaped' in a different way, and may contain, unescaped, brackets denoting objects or lists. These are replaced in the JSON string by tokens representing the string */
(
String_ID INT IDENTITY(1, 1),
StringValue NVARCHAR(MAX)
)
SELECT--initialise the characters to convert hex to ascii
@characters='0123456789abcdefghijklmnopqrstuvwxyz',
@SequenceNo=0, --set the sequence no. to something sensible.
/* firstly we process all strings. This is done because [{} and ] aren't escaped in strings, which complicates an iterative parse. */
@parent_ID=0;
WHILE 1=1 --forever until there is nothing more to do
BEGIN
SELECT
@start=PATINDEX('%[^a-zA-Z]["]%', @json collate SQL_Latin1_General_CP850_Bin);--next delimited string
IF @start=0 BREAK --no more so drop through the WHILE loop
IF SUBSTRING(@json, @start+1, 1)='"'
BEGIN --Delimited Name
SET @start=@Start+1;
SET @end=PATINDEX('%[^\]["]%', RIGHT(@json, LEN(@json+'|')-@start) collate SQL_Latin1_General_CP850_Bin);
END
IF @end=0 --no end delimiter to last string
BREAK --no more
SELECT @token=SUBSTRING(@json, @start+1, @end-1)
--now put in the escaped control characters
SELECT @token=REPLACE(@token, FROMString, TOString)
FROM
(SELECT
'\"' AS FromString, '"' AS ToString
UNION ALL SELECT '\\', '\'
UNION ALL SELECT '\/', '/'
UNION ALL SELECT '\b', CHAR(08)
UNION ALL SELECT '\f', CHAR(12)
UNION ALL SELECT '\n', CHAR(10)
UNION ALL SELECT '\r', CHAR(13)
UNION ALL SELECT '\t', CHAR(09)
) substitutions
SELECT @result=0, @escape=1
--Begin to take out any hex escape codes
WHILE @escape>0
BEGIN
SELECT @index=0,
--find the next hex escape sequence
@escape=PATINDEX('%\x[0-9a-f][0-9a-f][0-9a-f][0-9a-f]%', @token collate SQL_Latin1_General_CP850_Bin)
IF @escape>0 --if there is one
BEGIN
WHILE @index<4 --there are always four digits to a \x sequence
BEGIN
SELECT --determine its value
@result=@result+POWER(16, @index)
*(CHARINDEX(SUBSTRING(@token, @escape+2+3-@index, 1),
@characters)-1), @index=@index+1 ;
END
-- and replace the hex sequence by its unicode value
SELECT @token=STUFF(@token, @escape, 6, NCHAR(@result))
END
END
--now store the string away
INSERT INTO @Strings (StringValue) SELECT @token
-- and replace the string with a token
SELECT @JSON=STUFF(@json, @start, @end+1,
'@string'+CONVERT(NVARCHAR(5), @@identity))
END
-- all strings are now removed. Now we find the first leaf.
WHILE 1=1 --forever until there is nothing more to do
BEGIN
SELECT @parent_ID=@parent_ID+1
--find the first object or list by looking for the open bracket
SELECT @FirstObject=PATINDEX('%[{[[]%', @json collate SQL_Latin1_General_CP850_Bin)--object or array
IF @FirstObject = 0 BREAK
IF (SUBSTRING(@json, @FirstObject, 1)='{')
SELECT @NextCloseDelimiterChar='}', @type='object'
ELSE
SELECT @NextCloseDelimiterChar=']', @type='array'
SELECT @OpenDelimiter=@firstObject
WHILE 1=1 --find the innermost object or list...
BEGIN
SELECT
@lenJSON=LEN(@JSON+'|')-1
--find the matching close-delimiter proceeding after the open-delimiter
SELECT
@NextCloseDelimiter=CHARINDEX(@NextCloseDelimiterChar, @json,
@OpenDelimiter+1)
--is there an intervening open-delimiter of either type
SELECT @NextOpenDelimiter=PATINDEX('%[{[[]%',
RIGHT(@json, @lenJSON-@OpenDelimiter)collate SQL_Latin1_General_CP850_Bin)--object
IF @NextOpenDelimiter=0
BREAK
SELECT @NextOpenDelimiter=@NextOpenDelimiter+@OpenDelimiter
IF @NextCloseDelimiter<@NextOpenDelimiter
BREAK
IF SUBSTRING(@json, @NextOpenDelimiter, 1)='{'
SELECT @NextCloseDelimiterChar='}', @type='object'
ELSE
SELECT @NextCloseDelimiterChar=']', @type='array'
SELECT @OpenDelimiter=@NextOpenDelimiter
END
---and parse out the list or name/value pairs
SELECT
@contents=SUBSTRING(@json, @OpenDelimiter+1,
@NextCloseDelimiter-@OpenDelimiter-1)
SELECT
@JSON=STUFF(@json, @OpenDelimiter,
@NextCloseDelimiter-@OpenDelimiter+1,
'@'+@type+CONVERT(NVARCHAR(5), @parent_ID))
WHILE (PATINDEX('%[A-Za-z0-9@+.e]%', @contents collate SQL_Latin1_General_CP850_Bin))<>0
BEGIN
IF @Type='Object' --it will be a 0-n list containing a string followed by a string, number,boolean, or null
BEGIN
SELECT
@SequenceNo=0,@end=CHARINDEX(':', ' '+@contents)--if there is anything, it will be a string-based name.
SELECT @start=PATINDEX('%[^A-Za-z@][@]%', ' '+@contents collate SQL_Latin1_General_CP850_Bin)--AAAAAAAA
SELECT @token=SUBSTRING(' '+@contents, @start+1, @End-@Start-1),
@endofname=PATINDEX('%[0-9]%', @token collate SQL_Latin1_General_CP850_Bin),
@param=RIGHT(@token, LEN(@token)-@endofname+1)
SELECT
@token=LEFT(@token, @endofname-1),
@Contents=RIGHT(' '+@contents, LEN(' '+@contents+'|')-@end-1)
SELECT @name=stringvalue FROM @strings
WHERE string_id=@param --fetch the name
END
ELSE
SELECT @Name=null,@SequenceNo=@SequenceNo+1
SELECT
@end=CHARINDEX(',', @contents)-- a string-token, object-token, list-token, number,boolean, or null
IF @end=0
SELECT @end=PATINDEX('%[A-Za-z0-9@+.e][^A-Za-z0-9@+.e]%', @Contents+' ' collate SQL_Latin1_General_CP850_Bin)
+1
SELECT
@start=PATINDEX('%[^A-Za-z0-9@+.e][A-Za-z0-9@+.e]%', ' '+@contents collate SQL_Latin1_General_CP850_Bin)
--select @start,@end, LEN(@contents+'|'), @contents
SELECT
@Value=RTRIM(SUBSTRING(@contents, @start, @End-@Start)),
@Contents=RIGHT(@contents+' ', LEN(@contents+'|')-@end)
IF SUBSTRING(@value, 1, 7)='@object'
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, Object_ID, ValueType)
SELECT @name, @SequenceNo, @parent_ID, SUBSTRING(@value, 8, 5),
SUBSTRING(@value, 8, 5), 'object'
ELSE
IF SUBSTRING(@value, 1, 6)='@array'
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, Object_ID, ValueType)
SELECT @name, @SequenceNo, @parent_ID, SUBSTRING(@value, 7, 5),
SUBSTRING(@value, 7, 5), 'array'
ELSE
IF SUBSTRING(@value, 1, 7)='@string'
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, ValueType)
SELECT @name, @SequenceNo, @parent_ID, stringvalue, 'string'
FROM @strings
WHERE string_id=SUBSTRING(@value, 8, 5)
ELSE
IF @value IN ('true', 'false')
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, ValueType)
SELECT @name, @SequenceNo, @parent_ID, @value, 'boolean'
ELSE
IF @value='null'
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, ValueType)
SELECT @name, @SequenceNo, @parent_ID, @value, 'null'
ELSE
IF PATINDEX('%[^0-9]%', @value collate SQL_Latin1_General_CP850_Bin)>0
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, ValueType)
SELECT @name, @SequenceNo, @parent_ID, @value, 'real'
ELSE
INSERT INTO @hierarchy
(NAME, SequenceNo, parent_ID, StringValue, ValueType)
SELECT @name, @SequenceNo, @parent_ID, @value, 'int'
if @Contents=' ' Select @SequenceNo=0
END
END
INSERT INTO @hierarchy (NAME, SequenceNo, parent_ID, StringValue, Object_ID, ValueType)
SELECT '-',1, NULL, '', @parent_id-1, @type
--
RETURN
END
GO
CREATE FUNCTION ToXML
(
/*this function converts a JSONhierarchy table into an XML document. This uses the same technique as the toJSON function, and uses the 'entities' form of XML syntax to give a compact rendering of the structure */
@Hierarchy Hierarchy READONLY
)
RETURNS NVARCHAR(MAX)--use unicode.
AS
BEGIN
DECLARE
@XMLAsString NVARCHAR(MAX),
@NewXML NVARCHAR(MAX),
@Entities NVARCHAR(MAX),
@Objects NVARCHAR(MAX),
@Name NVARCHAR(200),
@Where INT,
@ANumber INT,
@notNumber INT,
@indent INT,
@CrLf CHAR(2)--just a simple utility to save typing!
--firstly get the root token into place
--firstly get the root token into place
SELECT @CrLf=CHAR(13)+CHAR(10),--just CHAR(10) in UNIX
@XMLasString ='<?xml version="1.0" ?>
@Object'+CONVERT(VARCHAR(5),OBJECT_ID)+'
'
FROM @hierarchy
WHERE parent_id IS NULL AND valueType IN ('object','array') --get the root element
/* now we simply iterate from the root token growing each branch and leaf in each iteration. This won't be enormously quick, but it is simple to do. All values, or name/value pairs within a structure can be created in one SQL Statement*/
WHILE 1=1
begin
SELECT @where= PATINDEX('%[^a-zA-Z0-9]@Object%',@XMLAsString)--find NEXT token
if @where=0 BREAK
/* this is slightly painful. we get the indent of the object we've found by looking backwards up the string */
SET @indent=CHARINDEX(char(10)+char(13),Reverse(LEFT(@XMLasString,@where))+char(10)+char(13))-1
SET @NotNumber= PATINDEX('%[^0-9]%', RIGHT(@XMLasString,LEN(@XMLAsString+'|')-@Where-8)+' ')--find NEXT token
SET @Entities=NULL --this contains the structure in its XML form
SELECT @Entities=COALESCE(@Entities+' ',' ')+NAME+'="'
+REPLACE(REPLACE(REPLACE(StringValue, '<', '<'), '&', '&'),'>', '>')
+ '"'
FROM @hierarchy
WHERE parent_id= SUBSTRING(@XMLasString,@where+8, @Notnumber-1)
AND ValueType NOT IN ('array', 'object')
SELECT @Entities=COALESCE(@entities,''),@Objects='',@name=CASE WHEN Name='-' THEN 'root' ELSE NAME end
FROM @hierarchy
WHERE [Object_id]= SUBSTRING(@XMLasString,@where+8, @Notnumber-1)
SELECT @Objects=@Objects+@CrLf+SPACE(@indent+2)
+'@Object'+CONVERT(VARCHAR(5),OBJECT_ID)
--+@CrLf+SPACE(@indent+2)+''
FROM @hierarchy
WHERE parent_id= SUBSTRING(@XMLasString,@where+8, @Notnumber-1)
AND ValueType IN ('array', 'object')
IF @Objects='' --if it is a lef, we can do a more compact rendering
SELECT @NewXML='<'+COALESCE(@name,'item')+@entities+' />'
ELSE
SELECT @NewXML='<'+COALESCE(@name,'item')+@entities+'>'
+@Objects+@CrLf++SPACE(@indent)+'</'+COALESCE(@name,'item')+'>'
/* basically, we just lookup the structure based on the ID that is appended to the @Object token. Simple eh? */
--now we replace the token with the structure, maybe with more tokens in it.
Select @XMLasString=STUFF (@XMLasString, @where+1, 8+@NotNumber-1, @NewXML)
end
return @XMLasString
end
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发表于 2015-2-11 11:43:01
