In a table there are like 113 columns. and there are two default records in the table, one is for unknown and another is for inapplicable. So, each column has its own default value to represent unknown and inapplicable.
I dont wanna write regular insert statement to get those two records.
so, I tried to insert each column using a cursor.
Got the names of columns for that table from information_schema.columns and tried to insert values from exact table in another location using "insert into select" statement, but the name of the columns that we get from information_schema
Declare #col_name varchar(50)
declare my_cur CURSOR for
select column_name from information_schema.columns
where table_name = 'tabl' and table_catalog = 'db'
and table_schema = 'dbo'
Fetch next from my_cur
into #col_name
while ##FETCH_STATUS = 0
BEGIN
Insert into db.dbo.tabl (***#col_name***)
select ***#col_name*** from openrowset('sqlncli', 'server=my_server; trusted_connection=yes;', db.dbo.tabl)
fetch next from my_cur into #col_name
end
close my_cur
deallocate my_cur
go
But, I did not realize that #col_name would be treated as string, rather than object (column)
Is there any work around for this case or any alternative solution.
I think that getting these defaults populated is the least of your problems.
I'd suggest taking a look at this: Fundamentals of Relational Database Design
And if you still want to do this, it might be better to retrieve all the defaults from the linked server, place them in a temp table, and then join to information_schema.columns to populate your table. You'll probably need to transpose the data to make it work.
You will have to generate the INSERT statement as dynamic SQL and then execute it
Declare #InsertStatement VarChar (Max)
SET #InsertStatement = ''
SET #InsertStatement = #InsertStatement + ' Insert into db.dbo.tabl (' + #col_name + ') '
SET #InsertStatement = #InsertStatement + ' select ' + #col_name + ' from openrowset(''sqlncli'', ''server=my_server''; '
Exec Sp_SQLExec #InsertStatement
Related
I'm using a search object query (found on the internet, wish I could give credit to the developer) to search database for the columns needed when I write queries. The output search object query allows me to enter the type of table to look in (partial name) as well as the column name (partial name) I'm trying to find. I've been attempting to modify the search object query so it returns the 1st value (Top 1) it finds. This would help me to easily see at a glance if the column has the particular type of data I'm looking for.
I've attempted to write it both as a stored procedure that I could pass two parameters (partial table and partial column name) and I've also tried using dynamic SQL (my first attempt at using it, so I'm a novice when it comes to use it). I had moderate success with the use of dynamic SQL, but can only get it to produce one result rather than be called multiple times for all the results in my search object output. The code I used is shown here:
-- This is the search object query found on internet
Use masterdb
Select a.name, b.name
From sysobjects a
Inner Join syscolumns b On a.id = b.id
Where b.name like '%Result%'
And a.name like '%Lab%'
Order By a.name, b.name
-- This is a separate query I used to test calling the data with dynamic SQL
DECLARE #value VARCHAR(100), #tablename VARCHAR(100)
SET #value = 'Result'
SET #tablename = 'LabSpecimen'
DECLARE #sqlText NVARCHAR(1000);
SET #sqlText = N'SELECT Top 1 ' + #value + ' FROM testndb.dbo.' + #tablename
EXEC (#sqlText)
If I use the search object query and search for tables that have lab and column names that have result, I might get output like this:
LabMain,ResultID
LabSpecimen,ResultCategory
LabSpecimen,ResultDate
LabSpecimen,Results
I would like to have the search object query pull data from the table in the first column and the column name in the 2nd column and return the first value it finds to give me a sample output for the given column name/table. Output would look like this:
LabMain,ResultID,E201812310001
LabSpecimen,ResultCategory,ExampleCategory
LabSpecimen,ResultDate,20181231
LabSpecimen,Results,34.20
Okay, I really didn't want to have to post an answer to this, but here goes.
So, the first, really-really-huge thing is: SQL Injection. SQL Injection is the #1 security vulnerability for something like a dozen years running, per OWASP. Basically, SQL Injection is where you use dynamic SQL that has any fragment of the sql command being populated by a user. So in the OP's case, this section here:
SET #value = 'Result'
SET #tablename = 'LabSpecimen'
DECLARE #sqlText NVARCHAR(1000);
SET #sqlText = N'SELECT Top 1 ' + #value + ' FROM testndb.dbo.' + #tablename
EXEC (#sqlText)
... if the end incarnation would be that #tableName and #value are populated by the user as part of their search? Then the user can do a 'search' that ends up injecting sql statements that the server runs directly; for a cheap example, imagine this for #value:
3' ; drop table #tableName --
... which would go ahead and drop every table that matches the #tablename you passed in.
Anyway, so, as we go through this problem, we're going to keep SQL Injection in mind at every step.
Problem #1: How to get the tables/columns that match.
You pretty much already nailed this. The only thing missing is to put it into a temp table so that you can loop through it (and limit it down to U-types, since otherwise you'll get stored procs and system tables.) I went ahead and had it also hit the Schema information - that way, if you have tables in different schemas, it'll still be able to get the results.
declare #tableNameFragment varchar(100) -- note: these top 4 lines will eventually
declare #columnNameFragment varchar(100) -- be changed to stored proc args
set #tableNameFragment = 'Performance' -- and populated by the user calling
set #columnNameFragment = 'status' -- the proc (instead of hard-coded.)
declare #entityMatches TABLE (TableName varchar(200), ColName varchar(128))
insert into #entityMatches
Select sch.TABLE_SCHEMA + '.' + sysobj.name as TableName, syscol.name as ColName
From sysobjects sysobj
Join syscolumns syscol On sysobj.id = syscol.id
Join INFORMATION_SCHEMA.TABLES sch on sch.TABLE_NAME = sysobj.name
where sysobj.xtype = 'U'
and (sysobj.name like '%' + isnull(#tableNameFragment,'') + '%')
and (syscol.name like '%' + isnull(#columnNameFragment,'') + '%')
Now, notice that while #tableNameFragment and #columnNameFragment are used, they're not used in a dynamic query. It doesn't matter if the user puts in something malicious into those values
Problem #2 - How to loop through your table
Basically, you're going to need a cursor. I hate cursors, but sometimes (like this one), they're necessary.
Problem #3 - How to actually do a dynamic query and get a result back
This is actually trickier than it looks. You can't do a raw EXEC() for a return value, nor can you simply have the cmd you're executing populating a variable - because EXEC (and SP_ExecuteSql operate in a different context, so they can't populate variables outside in your script.)
You need to use SP_ExecuteSQL, but specify a return variable getting populated by the interior sql command. For example:
declare #sqlCmd nvarchar(max)
declare #dynamicReturn varchar(max)
set #sqlCmd = 'select #retVal=1'
EXEC Sp_executesql #sqlCmd,
N'#retVal varchar(max) output',
#dynamicReturn output
select #dynamicReturn
Problem #4 - How to write your Dynamic command
Here's where things get dicey, since it's where we're using a dynamic SQL command. The important thing here is: you cannot use anything the user provided as an input. Which means, you can't use the variables #tableNameFragment or #columnNameFragment. You can use the values in the #entityMatches table, though. Why? Because the user didn't populate them. They got populated by the data in the sys tables - it doesn't matter if the user puts something nefarious in the input variables, that #entityMatches data simply holds the existing table/column names that match.
Also important: When you're working on code that could be a problem if a future dev down the line tweaks or copies/pastes - you should put comment warnings to illuminate the issue.
So, putting it all together? You'll have something that looks like this:
declare #tableNameFragment varchar(100) -- note: these top 4 lines will eventually
declare #columnNameFragment varchar(100) -- be changed to stored proc args
set #tableNameFragment = 'Performance' -- and populated by the user calling
set #columnNameFragment = 'status' -- the proc (instead of hard-coded.)
declare #entityMatches TABLE (TableName varchar(200), ColName varchar(128))
insert into #entityMatches
Select sch.TABLE_SCHEMA + '.' + sysobj.name as TableName, syscol.name as ColName
From sysobjects sysobj
Join syscolumns syscol On sysobj.id = syscol.id
Join INFORMATION_SCHEMA.TABLES sch on sch.TABLE_NAME = sysobj.name
where sysobj.xtype = 'U'
and (sysobj.name like '%' + isnull(#tableNameFragment,'') + '%')
and (syscol.name like '%' + isnull(#columnNameFragment,'') + '%')
declare #returnResults TABLE (TableName varchar(200), ColName varchar(128), FirstValue varchar(max))
declare Cur Cursor For select TableName,ColName from #entityMatches
declare #cursorTable varchar(200), #cursorColumn varchar(128)
open Cur
fetch Next from cur into #cursorTable,#cursorColumn
while ##FETCH_STATUS = 0
begin
-- Note: the variables #cursorTable, #cursorColumn are NOT user populated
-- but instead are populated from the Sys tables. Because of this,
-- this dynamic sql below is not SQL-Injection vulnerable (the entries
-- are not populated from user entry of any sort.)
-- Be very careful modifying the lines below to make sure you don't
-- introduce a vulnerability.
declare #sqlCmd nvarchar(max)
declare #dynamicReturn varchar(max)
set #sqlCmd = 'select top 1 #retVal=[' + #cursorColumn + '] from ' + #cursorTable
EXEC Sp_executesql #sqlCmd,
N'#retVal varchar(max) output',
#dynamicReturn output
insert into #returnResults values (#cursorTable, #cursorColumn, #dynamicReturn)
fetch Next from cur into #cursorTable,#cursorColumn
End
close cur
deallocate cur
select * from #returnResults
Create a stored procedure like below mention stored procedure.
Get the table and column name from sysobject & syscolumn and add it in hash table on the base of parameter of stored procedure. After that declare a cursor and in loop of cursor create a dynamic query of column and table name and get first row of current column from table of cursor loop. After that execute the query and update the result in the hash table. At the end of lookup select the Record from hash table. Check the below stored procedure. I hope that its helpful for you.
Create procedure Sp_GetSampleData
#TName varchar(200) = ''
as
Select
a.name TableName, b.name ColumnName,
CAST('' as varchar(max)) as SampleValue
into
#Tbl
from
sysobjects a
inner join
syscolumns b on a.id = b.id
where
(#TName='' or a.name = #TName)
order ny
a.name, b.name
declare #TableName varchar(200), #ColumnName varchar(200),
#sqlText nvarchar(max), #Val varchar(max)
declare Cur Cursor For
select TableName, ColumnName
from #Tbl
open Cur
fetch Next from cur into #TableName,#ColumnName
while ##FETCH_STATUS =0
begin
set #sqlText=''
set #Val=''
SET #sqlText = N'SELECT Top 1 #Val=[' + #ColumnName + '] FROM testndb.dbo.' + #TableName
EXEC Sp_executesql
#sqlText,
N'#Val varchar(max) output',
#Val output
print #sqlText
update #Tbl set SampleValue=#Val where TableName=#TableName and ColumnName =#ColumnName
fetch Next from cur into #TableName,#ColumnName
End
close cur
deallocate cur
select * from #Tbl
in my project (automation-testing) I am adding a lot of data into my Database, which supposed to be deleted after running all scenarios, but in rare occasions when execution crashes I am sometimes left with records that were not deleted.
For this reason, I decided in addition store all records that were created into additional table, where I store:
new of the table where new record was inserted
name of the field used for where clause in delete statement
id of the record in its table
Now I am trying to select all records from table above, and use it to create delete queries.
Is it possible to do it in single query?
SELECT * FROM AutomationTestingData AS atd
DELETE FROM atd.TableName WHERE atd.DeleteByField = atd.RecordId
Any help would be appreciated, regards.
Hi if i understand all what you're trying i think this can respond :
SET NOCOUNT ON;
DECLARE #query varchar(4000);
PRINT '-------- Deleting rows --------';
DECLARE deleting_cursor CURSOR FOR
SELECT 'DELETE FROM ' + atd.TableName + ' WHERE ' + atd.DeleteByField + ' = ' + atd.RecordId + ';'
FROM AutomationTestingData AS atd
OPEN deleting_cursor
FETCH NEXT FROM deleting_cursor
INTO #query
WHILE ##FETCH_STATUS = 0
BEGIN
EXEC(#Query)
FETCH NEXT FROM deleting_cursor
INTO #query
END
CLOSE deleting_cursor;
DEALLOCATE deleting_cursor;
CURSOR SQL : https://learn.microsoft.com/en-us/sql/t-sql/language-elements/declare-cursor-transact-sql?view=sql-server-2017
EXECUTE dynamic SQL Server : https://learn.microsoft.com/en-us/sql/t-sql/language-elements/execute-transact-sql?view=sql-server-2017
You could write a delete statement for each table, like this
delete from Company
where id in ( select RecordId from adt where adt.TableName = 'Company')
delete from PickListValues
where id in ( select RecordId from adt where adt.TableName = 'PickListValues')
Granted, its not really dynamic, but its still faster then dynamic sql and a cursor
Edit
IF you need it fully automatic, use dynamic sql like suggested by #pascalsanchez
I would alter the cursor however like this
declare deleting_cursor cursor for
select 'delete from ' + adt.TableName +
'where ' + adt.DeleteByField + ' in (select RecordID from adt where adt.TableName = ''' + adt.TableName + ''')
from AutomationTestingData AS atd
group by adt.TableName, adt.DeleteByField
you can use this syntax :
delete T1
from Table1 T1 join Table2.T2 on T1.SomeField=T2.SomeField
where Some Condition
I want to run the following SELECT query:
DECLARE #ColumnName nvarchar(50)
SET #ColumnName = 'AlarmID' -- actually these are calculated
-- by another SELECT but this isn't relevant
SELECT MIN(#ColumnName) FROM INSERTED
This doesn't work, it returns the value of #ColumnName instead of the actual data. How can I make this work?
I cannot put the SELECT into a string and run it with sp_executesql because I will lose access to the INSERTED table (this is running in a trigger).
EXEC('SELECT MIN(' + #ColumnName + ') FROM INSERTED')
Derived from the link smoore provided.
Use this if you want the minimum as a variable:
SELECT #columnName = MIN(#ColumnName) FROM YourTable
You can't really do that. Your best bet, depending on number of possible values of #ColumnName, is to dynamically set the field value with a case statement, or selectively run the right query using an IF statement:
SELECT CASE #ColumnName WHEN 'AlarmID' THEN MIN(AlarmID) WHEN 'AnotherField' THEN
MIN(AnotherField) END AS MinimumValue FROM INSERTED
OR
IF #ColumnName = 'AlarmID'
SELECT MIN(AlarmID) FROM INSERTED
ELSE
....
So far in the website I have only found stored procedures to list all the tables in a database, but what I really want to know is how to create a stored procedure in SQL Server to display all data of all tables in a specific database.
I don't want to join the tables and then display a huge table, I want to create some kind of loop that takes the first table of the database, performs a
SELECT * FROM <Table>
query, and then continues with the next table of the database and so on until all tables are displayed.
I know it should be easy but I have never created a stored procedure before so I don't know how to use the variables or go through the tables.
Thank you
Something like this should work:
CREATE Procedure [dbo].[procSelectAllFromAllTables]
AS
DECLARE #table nvarchar(500)
DECLARE #sql nvarchar(520)
DECLARE CursorSelect CURSOR FOR
select table_name from INFORMATION_SCHEMA.tables where table_name not like 'sys%'
OPEN CursorSelect
FETCH NEXT FROM CursorSelect
INTO #table
WHILE ##FETCH_STATUS = 0
BEGIN
SET #sql = 'select * from ' + #table
exec(#sql)
FETCH NEXT FROM CursorSelect
INTO #table
END
CLOSE CursorSelect
DEALLOCATE CursorSelect
RETURN
learn how to create a stored procedure
learn how to use variables in a stored procedure
Get a list of all the table names
use a cursor to create a while loop on a list of all table names
use dynamic sql on 'select * from ' + #tablename
As others have said, this is a silly idea from a practical standpoint, but as an academic exercise, it is fairly simple if you use a bit of dynamic sql and COALESCE(). No cursors or loops required.
DECLARE #SQL VARCHAR(MAX)
SELECT #SQL = COALESCE(#SQL, '') + ' SELECT * FROM ' + s.name + '.' + t.name
FROM sys.tables t INNER JOIN sys.schemas s ON s.schema_id = t.schema_id
EXEC #SQL
In SQL Server 2008, is there a way to access an object based on the OBJECT_ID?
[Edit] The example described below was solved using Andrew's suggestion in the comment, but I'm still curious about the general case. Can an object itself be retrieved using OBJECT_ID, or can it only be accessed indirectly by using the object name via sp_executesql?
My specific case is a stored procedure that uses several temporary tables. At the end of the procedure I want to dump the data from the temporary tables into actual tables for analysis (only if a debug switch is enabled).
The code for dumping the data is similar to this:
IF OBJECT_ID('tempdb..#MyTempTable', 'U') IS NOT NULL
BEGIN
IF OBJECT_ID('Debug_MyTempTable', 'U') IS NOT NULL
DROP TABLE Debug_MyTempTable
SELECT * INTO Debug_MyTempTable FROM #MyTempTable
END
This code block is repeated for each temporary table, so I would prefer to put it in a procedure and call it with a table name:
EXEC [dbo].[CreateDebugTable]
#tableName = 'MyTempTable'
I imagine the procedure would look something like:
CREATE PROCEDURE [dbo].[CreateDebugTable]
#tableName VARCHAR(50)
AS
BEGIN
IF OBJECT_ID('tempdb..#' + #tableName, 'U') IS NOT NULL
BEGIN
IF OBJECT_ID('dbo.Debug_' + #tableName, 'U') IS NOT NULL
DROP TABLE <Debug_TempTable>
SELECT * INTO <Debug_TempTable> FROM <#TempTable>
END
END
The procedure depends on being able to translate the OBJECT_ID of DebugTempTable and #TempTable into the actual tables (shown with <> in the code above). Is this possible?
[Edit]
This is the altered procedure using sp_executesql instead of explicit tables.
CREATE PROCEDURE [dbo].[CreateDebugTable]
#tableName VARCHAR(50)
AS
BEGIN
DECLARE #tmpTable VARCHAR(50) = '#' + #tableName
DECLARE #dboTable VARCHAR(50) = 'Debug_' + #tableName
DECLARE #sql NVARCHAR(100)
IF OBJECT_ID('tempdb..' + #tmpTable, 'U') IS NOT NULL
BEGIN
IF OBJECT_ID('dbo.' + #dboTable, 'U') IS NOT NULL
BEGIN
SET #sql = 'DROP TABLE ' + #dboTable
EXECUTE sp_executesql #sql
END
SET #sql = 'SELECT * INTO ' + #dboTable + ' FROM ' + #tmpTable
EXECUTE sp_executesql #sql
END
END
The object_id is just used as a key in the various metadata views. There is no TSQL syntax to SELECT from (or otherwise manipulate) objects based on their object_id.
If you have an object_id then in general you could use
SELECT QUOTENAME(OBJECT_SCHEMA_NAME(#object_id[,database_id])) +
'.' +
QUOTENAME(OBJECT_NAME(#object_id[,database_id]) )
To get the 2 part name of the object but for #temp tables this returns the long internal name rather than the short one that you can actually use in queries.