using information_schema_tables and concatenate - sql

Question

I want to know how can I use the information_schema_tables select query to look up #tablename, so that, that table's catalog and schema is shown, and then concatenate it together so that #tablename is displayed as table_catalog.table_schema.table name'?
At the moment I am just calling on the table name using select #tablename = Value
declare #tablename varchar(MAX)
declare #tableschema varchar(MAX)
declare #loop int = 1
select a.* into #tmp
from
(
select RID,
v.value('local-name(.)', 'VARCHAR(MAX)') 'Field',
v.value('./text()[1]', 'VARCHAR(MAX)') 'Value'
from #XMLTemp
cross apply Field.nodes ('/Record/*') x(v)
where v.value('local-name(.)', 'VARCHAR(MAX)') not in ('Update', 'Filter', 'Insert', 'Delete')
) as a
where RID = #loop
...
select Table_Catalog, Table_Schema
from Information_Schema.Tables
...
select #tablename = ''
select #tablename = Value
from #tmp
where Field='tableName'
and RID = #loop
...
print 'update ' + #tablename + '
...
select #tablename = Value from #tmp where Field = 'TableName'
...
set #loop = #loop+1

Answer 1

In SQL Server you can use "+" to concatenate strings.
declare #tablename varchar(MAX)
select #tablename = TABLE_CATALOG + '.' + TABLE_SCHEMA + '.' + TABLE_NAME
from INFORMATION_SCHEMA.TABLES
where TABLE_NAME = 'TableName'
Keep in mind that if your query returns multiple rows #tablename variable will contains the last value returned.

Answer 2

select quotename(db_name()) + '.' + quotename( schemas.name ) + '.' + quotename( tables.name )
from sys.tables
join sys.schemas on tables.schema_id = schemas.schema_id
A couple of notes: "Catalog" in ANSI speak is Database in SQL Server, so within a database it's pretty much a constant value - the name of the current database.
In SQL Server I find the system views are more consistent and reliable than INFORMATION_SCHEMA, which mostly works but has some quirky issues.

Answer 3

According to your last question I'd like to suggest the following UDF:
You pass in your XML and a catalog's name (or NULLor DEFAULT) and the same with the schema's name. The function will use COALESCE to use the right portion:
CREATE FUNCTION dbo.CreateUpdateStatement
(
#XmlData XML
,#CatalogName VARCHAR(100) = NULL
,#SchemaName VARCHAR(100) = NULL
)
RETURNS VARCHAR(MAX)
BEGIN
DECLARE #RetVal VARCHAR(MAX);
WITH XMLNAMESPACES('http://www.w3.org/2001/XMLSchema-instance' AS xsi)
SELECT #RetVal=
'UPDATE '
+ COALESCE(#CatalogName + '.',TheTable.TABLE_CATALOG + '.', '')
+ COALESCE(#SchemaName + '.',TheTable.TABLE_SCHEMA + '.', 'dbo.')
+ One.Record.value('TableName[1]','varchar(max)')
+ ' SET ' + One.Record.value('(Update/FieldName)[1]','varchar(max)') + '=''' + One.Record.value('(Update/NewValue)[1]','varchar(max)') + ''' '
+ ' WHERE ' + One.Record.value('KeyField[1]','varchar(max)') + '=''' + One.Record.value('TableRef[1]','varchar(max)') + ''';'
FROM #XmlData.nodes('/Task/Record') AS One(Record)
OUTER APPLY
(
SELECT TOP 1 TABLE_CATALOG,TABLE_SCHEMA,TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME=One.Record.value('TableName[1]','varchar(max)')
) AS TheTable;
RETURN #RetVal;
END
GO
This is how you call it (I used one existing table's name spz.dbo.AuditRow in one of my catalogs):
DECLARE #x xml=
'<Task xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Record>
<order>1</order>
<TableName>AuditRow</TableName>
<KeyField>ProductPersonID</KeyField>
<TableRef>32420</TableRef>
<Update>
<FieldName>StatusID</FieldName>
<OldValue>3</OldValue>
<NewValue>8</NewValue>
</Update>
</Record>
</Task>';
SELECT dbo.CreateUpdateStatement(#x,DEFAULT,DEFAULT);
--UPDATE spz.dbo.AuditRow SET StatusID='8' WHERE ProductPersonID='32420';
SELECT dbo.CreateUpdateStatement(#x,'MyCatalog',DEFAULT);
--UPDATE MyCatalog.dbo.AuditRow SET StatusID='8' WHERE ProductPersonID='32420';
SELECT dbo.CreateUpdateStatement(#x,DEFAULT,'MySchema');
--UPDATE spz.MySchema.AuditRow SET StatusID='8' WHERE ProductPersonID='32420';
SELECT dbo.CreateUpdateStatement(#x,'MyCatalog','MySchema');
--UPDATE MyCatalog.MySchema.AuditRow SET StatusID='8' WHERE ProductPersonID='32420';
You might execute this immediately with
EXEC (SELECT dbo.CreateUpdateStatement(#x,NULL,NULL));