I want to create code to dynamically rename a table based on stored procedure parameter
RENAME DBNAME.SCHEMANAME.T_TABLENAME1 TO DBNAME.SCHEMANAME.T_TABLENAME1_BKP
RENAME DBNAME.SCHEMANAME.T_TABLENAME2 TO DBNAME.SCHEMANAME.T_TABLENAME2_BKP
RENAME DBNAME.SCHEMANAME.T_TABLENAME3 TO DBNAME.SCHEMANAME.T_TABLENAME3_BKP
If I pass parameter as DBNAME.SCHEMANAME.<TABLENAME> to the SP, based on that it should rename, only "_TEMP" should be removed from the table name.
Below code throws error .
var V_RENAME = "ALTER TABLE IF EXISTS DBNAME.SCHEMANAME.T_" + INPUT_OBJECT_NAME + "RENAME TO DBNAME.SCHEMANAME.T_" + INPUT_OBJECT_NAME + "_BKP";
var V_CS_RENAME = snowflake.createStatement( {sqlText: V_RENAME} );
var V_RESULT_RENAME = V_CS_RENAME.execute();
Error
SQL compilation error: syntax error line 1 at position 78 unexpected 'TO'. At Statement.execute, line 43 position 51
Any help is appreciated .
You probably need to add a space before RENAME.
When dynamically constructing SQL statements it’s always a good idea to write out the statement, if you are facing issues, so that you can see what is actually being created and, if necessary, run it so you can see if it works as expected.
Related
If have a
DROP VIEW IF EXISTS mydatabase.myschema.myname;
CREATE OR REPLACE TABLE mydatabase.myschema.myname AS ...
that fails with error code 2203 SQL compilation error: Object found is of type 'TABLE', not specified type 'VIEW'..
My intention was to create a script to "convert" a set of existing views into tables (updated periodically via tasks). I wanted the script to be repeteable, so I thought I could DROP VIEW IF EXISTS xxx to drop the view if it exists but it seems that this will fail if there is already a table of the same name. So first time the script runs ok, it drops the view and creates the table but if I run the script again it will fail because now there is table with that same name.
So is there any way to ignore the error in the DROP VIEW IF EXISTS xxx or just to run the command if there is a VIEW with that name?
You have a number of options.
You can have your script read from the INFORMATION_SCHEMA to get a list of views and to delete. This SQL gets a list of all views except in the INFORMATION_SCHEMA.
select * from INFORMATION_SCHEMA.VIEWS where TABLE_SCHEMA <> 'INFORMATION_SCHEMA';
If you just want to drop the view names and avoid running into errors, here's a stored procedure you can call to try dropping a view without generating an error:
create or replace procedure DropView(viewName string)
returns string
language JavaScript
execute as OWNER
as
$$
var sql_command =
'drop view ' + VIEWNAME;
try {
var stmt = snowflake.createStatement( {sqlText: sql_command} );
var resultSet = stmt.execute();
while (resultSet.next()) {
outString = resultSet.getColumnValue('status');
}
}
catch (err) {
outString = err; // Return a success/error indicator.
}
return outString;
$$;
If you want to loop through every database and schema in the entire account, I wrote a stored procedure to do that. It's designed for dependency checking on all views, but could be modified to delete them too.
https://snowflake.pavlik.us/index.php/2019/10/14/object-dependency-checking-in-snowflake
My suggestion would be to create a stored procedure that loops through all of your views and creates tables from them. In that stored procedure, you could check to see if the object exists already as a table and skip that object.
I'm trying to creating a table in a SQL Server database using FireDAC. However, instead of using the index name I provide, FireDAC uses a bad index name, raising an exception and the table does not get created. Am I doing something wrong? If not, is there a work-around?
Note that I'm using the valid database schema name cnf for TableName. I specifically need to create the table in a schema.
Simplest test case:
var
Connection: TFDConnection;
Table: TFDTable;
begin
Connection := TFDConnection.Create(nil);
Table := TFDTable.Create(nil);
try
Connection.Params.Add ('DriverID=MSSQL');
Connection.Params.Add ('OSAuthent=No');
Connection.Params.Add ('User_Name=sa');
Connection.Params.Add ('Password=XXXXXX');
Connection.Params.Add ('Server=DAVE-DELL\MSSQLSERVER2016');
Connection.Params.Add ('Database=PROJECT_DB');
Connection.Params.Add ('MARS=No');
Connection.Open;
Table.Connection := Connection;
Table.TableName := 'cnf.TestTable';
Table.FieldDefs.Add ('TableID', ftAutoInc, 0, true);
Table.FieldDefs.Add ('Field1', ftInteger, 0, true);
Table.FieldDefs.Add ('Field2', ftstring, 100, true);
Table.IndexDefs.Add ('PK_XYZ', 'TableID', [ixPrimary]); // should use this index name!
Table.CreateTable (true);
finally
Table.Free;
Connection.Free;
end;
end;
An exception is raised:
[FireDAC][Phys][ODBC][Microsoft][SQL Server Native Client 11.0][SQL Server]Incorrect syntax near '.'.
Running SQL Server Profiler shows me that FireDAC is trying to create the index using the following SQL code:
ALTER TABLE temp.TestTable ADD CONSTRAINT [cnf].[PK_TestTable] PRIMARY KEY (TableID)
And, of course, [cnf].[PK_TestTable] is not a valid index name in T-SQL, which is the crux of the problem.
If I remove the line Table.IndexDefs.Add, the table is created properly, but without the index.
If I replace that line with the following, it gives the same problem:
with Table.IndexDefs.AddIndexDef do begin
Name := 'PK_XYZ';
Options := [ixPrimary];
Fields := 'TableID';
end;
If I replace setting the table name with the following, it gives the same problem:
Table.TableName := 'TestTable';
Table.SchemaName := 'cnf';
Why is it using it's own (wrong) index name, instead of the name I gave it? (i.e. PK_XYZ)
Embarcadero® Delphi 10.1 Berlin Version 24.0.25048.9432
SQL Server 2016 (SP2-CU4) - 13.0.5233.0 (X64)
Am I doing something wrong?
Why is it using it's own (wrong) index name, instead of the name I gave it?
You seem to be doing everything just right. The issue is with the generated SQL command as you have tracked that down. SQL Server doesn't allow schema name in constraint name when adding a constraint using ALTER TABLE. Constraints created this way automatically become part of schema of the related table, however you should later use schema name when referring to the constraint:
SELECT OBJECT_ID('cnf.PK_XYZ')
Now where do the things go wrong? FireDAC uses TFDPhysCommandGenerator and its ancestors to generate SQL commands for specific DBMS. Your call to CreateTable method results in call to TFDPhysCommandGenerator.GetCreatePrimaryKey, which is responsible for generating SQL for primary key. It also contains this code:
sTab := GetFrom;
FConnMeta.DecodeObjName(sTab, rName, nil, [doUnquote]);
rName.FObject := 'PK_' + rName.FObject;
Result := 'ALTER TABLE ' + sTab + ' ADD CONSTRAINT ' +
FConnMeta.EncodeObjName(rName, nil, [eoQuote, eoNormalize]) + ' PRIMARY KEY (';
What this code does is that it takes your fully qualified table name (sTab) splits it (DecodeObjName) into parts (rName) prepends 'PK_' to table name and joins the parts (EncodeObjName) back to fully qualified name, which is then used as the constraint name for your primary key. Now we can clearly see that command generator ignores your index name and generates erroneous T-SQL. This can either be a bug or just a not supported feature. EMBT has to make decision on that. I'd recommend reporting it as a bug.
Is there a work-around?
Yes, you can either hook problematic method or you can override it in your own derived class. Implementation none of these is trivial and due to legal issues I'm not going to extend it here, because I would have to duplicate the original FireDAC code.
As for the syntax error adding these lines to 'TFDPhysCommandGenerator.GetCreatePrimaryKey' implementation after DecodeObjName would fix the issue:
rName.FCatalog := '';
rName.FSchema := '';
rName.FBaseObject := '';
rName.FLink := '';
Fixing constraint name is going to be more cumbersome than that, because the method only receives index column names as argument and has no obvious access to original IndexDefs where you could just use index name as primary key constraint name. Gaining access to index name from there would also allow you to get rid of decoding/encoding table name into index name. This process, however, could be essential for other DMBS's than SQL Server.
PS: If only half of all the questions were written in this manner ... Thank you for this wonderful question.
I'm stumped on something which should be very straight-forward. I have a SQL Server database, and I'm trying to update a non-nullable varchar or nvarchar field with an empty string. I know it's possible, because an empty string '' is not the same thing as NULL. However, using the TADOQuery, it is not allowing me to do this.
I'm trying to update an existing record like so:
ADOQuery1.Edit;
ADOQuery1['NonNullFieldName']:= '';
//or
ADOQuery1.FieldByName('NonNullFieldName').AsString:= '';
ADOQuery1.Post; //<-- Exception raised while posting
If there is anything in the string, even just a single space, it saves just fine, as expected. But, if it is an empty string, it fails:
Non-nullable column cannot be updated to Null.
But it's not null. It's an empty string, which should work just fine. I swear I've passed empty strings many, many times in the past.
Why am I getting this error, and what should I do to resolve it?
Additional details:
Database: Microsoft SQL Server 2014 Express
Language: Delphi 10 Seattle Update 1
Database drivers: SQLOLEDB.1
Field being updated: nvarchar(MAX) NOT NULL
I can reproduce your reported problem using the code below with SS2014, the OLEDB driver and
Seattle and the difference in behaviour when the table has been created with MAX as the column size and a specific number (4096 in my case). I thought I would post this is as an alternative
answer because it not only shows how to investigate this difference systematically
but also identifies why this difference arises (and hence how to avoid it in future).
Please refer to and execute the code below, as written, i.e. with the UseMAX define
active.
Turning on "Use Debug DCUs" in the the project options before executing the code, immediately
reveals that the described exception occurs in Data.Win.ADODB at line 4920
Recordset.Fields[TField(FModifiedFields[I]).FieldNo-1].Value := Data
of TCustomADODataSet.InternalPost and the Debug evaluation window reveals that
Data at this point is Null.
Next, notice that
update jdtest set NonNullFieldName = ''
executes in an SSMS2014 Query window without complaint (Command(s) completed successfully.), so it seems that the
fact that Data is Null at line 4920 is what is causing the problem and the next question is "Why?"
Well, the first thing to notice is that the form's caption is displaying ftMemo
Next, comment out the UseMAX define, recompile and execute. Result: No exception
snd notice that the form's caption is now displaying ftString.
And that's the reason: Using a specific number for the column size means that
the table metadata retrieved by the RTL causes the client-side Field to be created
as a TStringField, whose value you can set by a string assignment statement.
OTOH, when you specify MAX, the resulting client-side Field is of type ftMemo,
which is one of Delphi's BLOB types and when you assign
string values to an ftMemo field, you are at the mercy of code in Data.DB.Pas , which does all the reading (and writing) to the record buffer using a TBlobStream. The problem with that is that as far as I can see, after a lot of experiments and tracing through the code, the way a TMemoField uses a BlobStream fails to properly distinguish between updating the field contents to '' and setting the field's value to Null (as in System.Variants).
In short, whenever you try to set a TMemoField's value to an empty string, what actually happens is that the field's state is set to Null, and this is what causes the exception in the q. AFAICS, this is unavoidable, so no work-around is obvious, to me at any rate.
I have not investigated whether the choice between ftMemo and ftString is made by the Delphi RTL code or the MDAC(Ado) layer it sits upon: I would expect it is actually determined by the RecordSet TAdoQuery uses.
QED. Notice that this systematic approach to debugging has revealed the
problem & cause with very little effort and zero trial and error, which was
what I was trying to suggest in my comments on the q.
Another point is that this problem could be tracked down entirely without
resorting to server-side tools including the SMSS profiler. There wasn't any need to use the profiler to inspect what the client was sending to the server
because there was no reason to suppose that the error returned by the server
was incorrect. That confirms what I said about starting investigation at the client side.
Also, using a table created on the fly using IfDefed Sql enabled the problem effectively to be isolated in a single step by simple observation of two runs of the app.
Code
uses [...] TypInfo;
[...]
implementation[...]
const
// The following consts are to create the table and insert a single row
//
// The difference between them is that scSqlSetUp1 specifies
// the size of the NonNullFieldName to 'MAX' whereas scSqlSetUp2 specifies a size of 4096
scSqlSetUp1 =
'CREATE TABLE [dbo].[JDTest]('#13#10
+ ' [ID] [int] NOT NULL primary key,'#13#10
+ ' [NonNullFieldName] VarChar(MAX) NOT NULL'#13#10
+ ') ON [PRIMARY]'#13#10
+ ';'#13#10
+ 'Insert JDTest (ID, [NonNullFieldName]) values (1, ''a'')'#13#10
+ ';'#13#10
+ 'SET ANSI_PADDING OFF'#13#10
+ ';';
scSqlSetUp2 =
'CREATE TABLE [dbo].[JDTest]('#13#10
+ ' [ID] [int] NOT NULL primary key,'#13#10
+ ' [NonNullFieldName] VarChar(4096) NOT NULL'#13#10
+ ') ON [PRIMARY]'#13#10
+ ';'#13#10
+ 'Insert JDTest (ID, [NonNullFieldName]) values (1, ''a'')'#13#10
+ ';'#13#10
+ 'SET ANSI_PADDING OFF'#13#10
+ ';';
scSqlDropTable = 'drop table [dbo].[jdtest]';
procedure TForm1.Test1;
var
AField : TField;
S : String;
begin
// Following creates the table. The define determines the size of the NonNullFieldName
{$define UseMAX}
{$ifdef UseMAX}
S := scSqlSetUp1;
{$else}
S := scSqlSetUp2;
{$endif}
ADOConnection1.Execute(S);
try
ADOQuery1.Open;
try
ADOQuery1.Edit;
// Get explicit reference to the NonNullFieldName
// field to make working with it and investigating it easier
AField := ADOQuery1.FieldByName('NonNullFieldName');
// The following, which requires the `TypInfo` unit in the `USES` list is to find out which exact type
// AField is. Answer: ftMemo, or ftString, depending on UseMAX.
// Of course, we could get this info by inspection in the IDE
// by creating persistent fields
S := GetEnumName(TypeInfo(TFieldType), Ord(AField.DataType));
Caption := S; // Displays `ftMemo` or `ftString`, of course
AField.AsString:= '';
ADOQuery1.Post; //<-- Exception raised while posting
finally
ADOQuery1.Close;
end;
finally
// Tidy up
ADOConnection1.Execute(scSqlDropTable);
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
Test1;
end;
The problem occurs when using MAX in the data type. Both varchar(MAX) and nvarchar(MAX) exploit this behavior. When removing MAX and replacing it with a large number, such as 5000, then it allows empty strings.
I want to add a new parameter to an existing stored procedure. Body of this procedure may have been already customized by users so I can't drop and recreate it. I don't need to modify the body, just the signature.
So I thought to do a replacement of the last existing parameter by itself + the new parameter.
replace(OBJECT_DEFINITION (OBJECT_ID(id)),'#last_param varchar(max)=null','#last_param varchar(max)=null, #new_param varchar(max)=null')
It works fine if the following string is found
#last_param varchar(max)=null
but doesn't work if there is spaces in the string.
I would like to use a regex to be sure it works in all cases but I'm not sure it's possible in SQL Server.
Can you help me please ?
Thanks
SQL Server does not natively support regular expressions. You'll have to look at more manual string-analyzing with the available string functions. Something like this:
set #obDef = OBJECT_DEFINITION(OBJECT_ID(id))
set #startLastParam = PATINDEX('%#last_param%varchar%(%max%)%=%null%', #obDef)
if #startLastParam = 0 begin
-- handle lastParam not found
end else begin
set #endLastParam = CHARINDEX('null', #obDef, #startLastParam) + 4 -- 4 = len('null')
set #newDef = STUFF(#obDef, #endLastParam, 0, ', #new_param varchar(max)=null')
end
This isn't very fool-proof/safe though. PATINDEX() only gives you the same % wildcard you know from LIKE, it may match no character, it may match half the stored proc to find the word max somewhere entirely outside the signature.
So don't just run this in your customers production ;) but if you are certain about the current stored proc signature, this might just do the trick for you.
How do I correctly extract specific info from an sql error message number 547?
Info Required:
Table Name
Constraint Name
Column Name
Code:
Try
....
Catch ex As System.Data.SqlClient.SqlException
If ex.Number = 547 Then
End If
End Try
Sample message:
UPDATE statement conflicted with COLUMN CHECK constraint
'CK_Birthdate'. The conflict occurred in database 'Northwind', table
'Employees', column 'BirthDate'.
There is no straight forward way of getting these pieces of information separately.
It all gets concatenated into the error message.
You can use select * from sys.messages where message_id=547 to see the various different language formats of the message that you would need to deal with in order to extract the constituent parts then perhaps use regular expressions with capturing groups based around this information.
In addition to queries, here's a powershell script which wraps the sys.messages queries.
http://blogs.msdn.com/b/buckwoody/archive/2009/04/30/and-the-winner-is-get-sql-server-error-messages-from-powershell.aspx
its true there is no straight way to fix this but I did this insted
var str = sqlException.Message.ToString();
var strlist = str.Split(',', StringSplitOptions.RemoveEmptyEntries);
var streplace = strlist[1];
streplace = streplace.Replace("table \"dbo.", "");
streplace = streplace.Replace("\"", ""); //this will get the data table name
streplace = string.Concat(streplace.Select(x => Char.IsUpper(x) ? " " + x : x.ToString())).TrimStart(' ');