In connection with data replication from SQL Server to DB2 I have the following question:
On DB2 I have a table containing (for simplicity) two columns: COL1 and COL2.
COL1 is defined as CHAR(20). COL2 is defined as CHAR(10).
COL1 is replicated from SQL by converting a string into hex, e.g. "abcdefghij" to "6162636465666768696A" or "1111111111" to "31313131313131313131" by using the following SQL query:
CONVERT(char(20), cast(#InputString as binary) 2)
where #InputString would be "abedefghij".
In other words COL1 contains the hex value, but as a string (sorry if the wording is incorrect).
I need to convert the hex value back to a string and put this value into COL2.
What should the SQL query be on DB2 to do the convertion? I know how to do this on SQL Server, but not on DB2.
Note: The reason the hex-value is not pre-fixed with "0x" is because style 2 is used in the CONVERT statement.
select hex('A') from sysibm.sysdummy1;
returns 41.
and
select x'41' from sysibm.sysdummy1;
gives you 'A'. So you can put that in a for loop and loop through each pair of hex characters to arrive at your original string. Or you can write your own unhex function.
Taken from dbforums.com /db2/1627076-display-hex-columns.html (edit Nov 2020: original source link is now a spam site)
DB2 has built-in encoding/decoding.
For OPs question, use....
select CAST(ColumnName as char(20) CCSID 37) as ColumnName from TableName where SomeConditionExists
http://www-01.ibm.com/support/knowledgecenter/SSEPEK_10.0.0/com.ibm.db2z10.doc.intro/src/tpc/db2z_introcodepage.dita
This is one of most close topics to subject of my problem:
I have lost 2 days to figure out how to migrate XML files stored in DB2 BLOB field using SQL Developer.
(Yes, migrating to and doing the queries from SQL Developer - we are migrating data to Oracle from DB2, so we were using this tool)!
How to show XML file/string stored in BLOB?
Let's start with, what the problem was:
Data in BLOB was a XML file.
When selected in query, got:
When casted, like:
select CAST(BLOBCOLUMN as VARCHAR(1000)) from TABLE where id = 100;
output was in HEX:
Nothing worked... Not even the solution from the links in this topic.
!NOTHING!
By mistake found a solution:
CREATE FUNCTION in DB2:
CREATE FUNCTION unhex(in VARCHAR(32000) FOR BIT DATA)
RETURNS VARCHAR(32000)
LANGUAGE SQL
CONTAINS SQL
DETERMINISTIC NO EXTERNAL ACTION
BEGIN ATOMIC
RETURN in;
END
Run SELECT:
select UNHEX( CAST(BLOBCOLUMN as VARCHAR(32000) FOR BIT DATA)) from TABLE where id = 100;
Result:
I use this to convert FOR BIT DATA to characters:
cast (colvalue as varchar(2000) ccsid ebcdic for sbcs data)
Related
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 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
I have a text string stored as a BLOB data type in a database. I want to extract it by an SQL select query, but I have problems converting/casting from BLOB to readable text.
I've tried e.g.
select convert(nvarchar(40),convert(varbinary(40),BLOBTextToExtract))
from [NavisionSQL$Customer]
I guess I need something similar, but I can't figure out exactly what I need to do the conversion. Can somebody please give me some directions?
Regards
The accepted answer works for me only for the first 30 characters.
This works for me:
select convert(varchar(max), convert(varbinary(max),myBlobColumn)) FROM table_name
Problem was apparently not the SQL server, but the NAV system that updates the field. There is a compression property that can be used on BLOB fields in NAV, that is not a part of SQL Server. So the custom compression made the data unreadable, though the conversion worked.
The solution was to turn off compression through the Object Designer, Table Designer, Properties for the field (Shift+F4 on the field row).
After that the extraction of data can be made with e.g.:
select convert(varchar(max), cast(BLOBFIELD as binary))
from Table
Thanks for all answers that were correct in many ways!
It depends on how the data was initially put into the column. Try either of these as one should work:
SELECT CONVERT(NVarChar(40), BLOBTextToExtract)
FROM [NavisionSQL$Customer];
Or if it was just varchar...
SELECT CONVERT(VarChar(40), BLOBTextToExtract)
FROM [NavisionSQL$Customer];
I used this script to verify and test on SQL Server 2K8 R2:
DECLARE #blob VarBinary(MAX) = CONVERT(VarBinary(MAX), 'test');
-- show the binary representation
SELECT #blob;
-- this doesn't work
SELECT CONVERT(NVarChar(100), #blob);
-- but this does
SELECT CONVERT(VarChar(100), #blob);
Can you try this:
select convert(nvarchar(max),convert(varbinary(max),blob_column)) from table_name
Found this...
bcp "SELECT top 1 BlobText FROM TableName" queryout "C:\DesinationFolder\FileName.txt" -T -c'
If you need to know about different options of bcp flags...
http://msdn.microsoft.com/en-us/library/ms162802.aspx
CREATE OR REPLACE FUNCTION HASTANE.getXXXXX(p_rowid in rowid) return VARCHAR2
as
l_data long;
begin
select XXXXXX into l_data from XXXXX where rowid = p_rowid;
return substr( l_data, 1, 4000);
end getlabrapor1;
I need the text (representation) of a id field in SQL Server 2005. Is there a way, we can generate the textual representation of the id field?
For instance, if the id field reads as 0x00000000000002F0, I need the text value of 0x00000000000002F0 so that I can run SUBSTR operations on the same.
Constraints
I am not allowed to create a stored procedure in the Database (as creation of SP is not allowed)
Thanks!
You can convert unicode strings to binary using
SELECT CONVERT(VARBINARY(40),N'Hello World')
(returns 0x480065006C006C006F00200057006F0072006C006400)
Convert from binary back to unicode using
SELECT CONVERT(NVARCHAR(20), 0x480065006C006C006F00200057006F0072006C006400)
(returns 'Hello World')
Whilst it's not immediately obvious to me why you would want to do this for comparison purposes (as opposed to matching binary values), the undocumented function sys.fn_varbintohexstr should do the trick
declare #vb binary(8)
,#vc varchar(20)
set #vb = 0x00000000000002F0
set #vc = sys.fn_varbintohexstr(#vb)
--prove that this works by concatenating a string to the varchar value
select #vb, '#' + #vc
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