I am using SQL Server 2005 and JSP. I want to add column having name as string object value.
String dr="Doctor1";
stat1=conn.createStatement();
stat1.executeUpdate("ALTER TABLE dbo.PHPL ADD '"+dr+"' NVARCHAR(255) Null");
It is giving error near column name.I think I am mistaking with syntax. Please help.
String dr="Doctor1";
stat1=conn.createStatement();
stat1.executeUpdate("ALTER TABLE dbo.PHPL ADD "+dr+" NVARCHAR(255) Null");
that works fine.
A couple of issues here
You need to use execute, not executeUpdate. Altering a table is a DDL command, not insert, update or delete
As KittenLS has pointed out, the syntax for ALTER TABLE doesn't need quotes. However, you should use '[]' around to escape spaces, keywords, etc.
i.e.
stat1.execute("ALTER TABLE dbo.PHPL ADD [" + dr + "] NVARCHAR(255) Null");
Related
ALTER TABLE tableName
MODIFY COLUMN columnName VARCHAR (256);
Error :
Incorrect syntax near 'VARCHAR'
The syntax for modifying a column definition is depending on used database. For Microsoft SQL Server for example, you would need to replace MODIFY COLUMN with ALTER COLUMN.
For better help you should specify your database type.
I've got a front table that essentially matches our SSMS database table t_myTable. Some columns I'm having problems with are those with numeric data types in the db. They are set to allow null, but from the front end when the user deletes the numeric value and tries to send a blank value, it's not posting to the database. I suspect because this value is sent back as an empty string "" which does not translate to the null allowable data type.
Is there a trigger I can create to convert these empty strings into null on insert and update to the database? Or, perhaps a trigger would already happen too late in the process and I need to handle this on the front end or API portion instead?
We'll call my table t_myTable and the column myNumericColumn.
I could also be wrong and perhaps this 'empty string' issue is not the source of my problem. But I suspect that it is.
As #DaleBurrell noted, the proper place to handle data validation is in the application layer. You can wrap each of the potentially problematic values in a NULLIF function, which will convert the value to a NULL if an empty string is passed to it.
The syntax would be along these lines:
SELECT
...
,NULLIF(ColumnName, '') AS ColumnName
select nullif(Column1, '') from tablename
SQL Server doesn't allow to convert an empty string to the numeric data type. Hence the trigger is useless in this case, even INSTEAD OF one: SQL Server will check the conversion before inserting.
SELECT CAST('' AS numeric(18,2)) -- Error converting data type varchar to numeric
CREATE TABLE tab1 (col1 numeric(18,2) NULL);
INSERT INTO tab1 (col1) VALUES(''); -- Error converting data type varchar to numeric
As you didn't mention this error, the client should pass something other than ''. The problem can be found with SQL Profiler: you need to run it and see what exact SQL statement is executing to insert data into the table.
I'm using stored procedure to delete a row from MSSQL database based on a column that uses nvarchar(100) and Persian language.
when i want to insert into this column, i use the word N before the record to be able to perform the insert operation :
insert into materialPrice values( N'persian word',1000,100,0,0,0,0)
the problem is when i want to delete the same record, stored procedure does not work :
create proc spRemoveMaterial
#materialName nvarchar(100)
as
begin
delete from materialPrice where materialName = #materialName
end
I've tried to use N before #materialName but it returend syntax error. how could it be done ?
The N is a marker that causes the string literal to be represented in Unicode--implying that you are inserting into a Unicode column.
You should be able to convert the variable to Unicode with cast. Something like:
cast(#materialName as nvarchar(100))
With the correct type (nchar or nvarchar) and length to match the column.
The problem was with the database collation, following code has fixed it :
ALTER database MaterialDB COLLATE Persian_100_CI_AS
I ran these quires in my SQL server
select cast('<Answers>
<AnswerDescription> ϱπΩ÷√νƞµΔϒᵨλθ→%° </AnswerDescription>
</Answers>' as xml)
select ' ϱπΩ÷√νƞµΔϒᵨλθ→%°'
And got the following results
<Answers>
<AnswerDescription> ?pO÷v??µ??????%° </AnswerDescription>
</Answers>
and
" ?pO÷v??µ??????%°"
How to make my SQL server store or display these values as they are being sent from Application ?
In SQL Server, scalar string values are cast to VARCHAR by default.
Your example can be made to work by indicating that the strings should be treated as NVARCHAR by adding N before the opening single quote:
select cast(N'<Answers>
<AnswerDescription> ϱπΩ÷√νƞµΔϒᵨλθ→%° </AnswerDescription>
</Answers>' as xml)
select N' ϱπΩ÷√νƞµΔϒᵨλθ→%°'
If these strings are being incorrectly stored in the database, it is likely that they are being implicitly cast to VARCHAR at some point during insertion (e.g. INSERT). It's also possible that they are being stored correctly and are cast to VARCHAR on retrieval (e.g. SELECT).
If you add some code to the question showing how you're inserting data and the datatypes of the target tables, it should be possible to provide more detailed assistance.
I believe its problem with incorectly set character set,
change charecter set to UTF8.
I just tested it on my MySQL database, i changed character set to utf8-bin using
ALTER TABLE `tab1` CHANGE `test` `test` VARCHAR( 255 ) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL
worked without any problem
How do you add a string to a column in SQL Server?
UPDATE [myTable] SET [myText]=' '+[myText]
That doesn't work:
The data types varchar and text are incompatible in the add operator.
You would use concat on MySQL, but how do you do it on SQL Server?
like said before best would be to set datatype of the column to nvarchar(max), but if that's not possible you can do the following using cast or convert:
-- create a test table
create table test (
a text
)
-- insert test value
insert into test (a) values ('this is a text')
-- the following does not work !!!
update test set a = a + ' and a new text added'
-- but this way it works:
update test set a = cast ( a as nvarchar(max)) + cast (' and a new text added' as nvarchar(max) )
-- test result
select * from test
-- column a contains:
this is a text and a new text added
Stop using the TEXT data type in SQL Server!
It's been deprecated since the 2005 version. Use VARCHAR(MAX) instead, if you need more than 8000 characters.
The TEXT data type doesn't support the normal string functions, while VARCHAR(MAX) does - your statement would work just fine, if you'd be using just VARCHAR types.
The + (String Concatenation) does not work on SQL Server for the image, ntext, or text data types.
In fact, image, ntext, and text are all deprecated.
ntext, text, and image data types will
be removed in a future version of
MicrosoftSQL Server. Avoid using these
data types in new development work,
and plan to modify applications that
currently use them. Use nvarchar(max),
varchar(max), and varbinary(max)
instead.
That said if you are using an older version of SQL Server than you want to use UPDATETEXT to perform your concatenation. Which Colin Stasiuk gives a good example of in his blog post String Concatenation on a text column (SQL 2000 vs SQL 2005+).
UPDATE test SET a = CONCAT(a, "more text")
hmm, try doing CAST(' ' AS TEXT) + [myText]
Although, i am not completely sure how this will pan out.
I also suggest against using the Text datatype, use varchar instead.
If that doesn't work, try ' ' + CAST ([myText] AS VARCHAR(255))
To Join two string in SQL Query use function CONCAT(Express1,Express2,...)
Like....
SELECT CODE, CONCAT(Rtrim(FName), " " , TRrim(LName)) as Title FROM MyTable