how to fetch SSRS embedded data sources connection string from SQL Query,
below one capture Shared Data-source connection string,
;WITH XMLNAMESPACES -- XML namespace def must be the first in with clause.
(DEFAULT 'http://schemas.microsoft.com/sqlserver/reporting/2006/03/reportdatasource'
,'http://schemas.microsoft.com/SQLServer/reporting/reportdesigner'
AS rd)
,SDS AS
(SELECT SDS.name AS SharedDsName
,SDS.[Path]
,CONVERT(xml, CONVERT(varbinary(max), content)) AS DEF
FROM dbo.[Catalog] AS SDS
WHERE SDS.Type = 5) -- 5 = Shared Datasource
SELECT CON.[Path]
,CON.SharedDsName
,CON.ConnString
FROM
(SELECT SDS.[Path]
,SDS.SharedDsName
,DSN.value('ConnectString[1]', 'varchar(150)') AS ConnString
FROM SDS
CROSS APPLY
SDS.DEF.nodes('/DataSourceDefinition') AS R(DSN)
) AS CON
ORDER BY CON.[Path]
,CON.SharedDsName;