I have DB2 table having following structure
CREATE TABLE DUMMY
(
ID CHARACTER(10) NOT NULL,
RECORD XML NOT NULL
)
I want to use XQUERY to select data in RECORD column on the basis of ID. and do some XQUERY operations on the data present in RECORD column.
eg: I want to select RECORD having ID 1.
You can use the db2-fn:sqlquery function to do this. See the documentation.
Related
I need to convert text data in a table to large object data in another table. So the table structure is :-
Employee->
id (character varying(130)),name (character varying(130)), description (text)
EmployeeDetailed ->
detailed_id(character varying(130)), desc_lob (oid)
What query can I run in order to transfer all the rows from Employee table to EmployeeDetailed table so that detailed_id would be populated from Employee's id columns and description would be converted to large object and oid would be inserted in desc_lob.
Can I use lo_import(), would it help here?
lo_import() is a client interface command. You can use an INSERT statement, using the result of a SELECT, and use lo_from_bytea inside that SELECT clause:
INSERT INTO EmployeeDetailed (detailed_id, desc_lob)
SELECT id, lo_from_bytea(0, convert_to(description, 'LATIN1'))
FROM Employee
Change LATIN1 for whatever encoding you might like (see this answer)
I would like to implement an append-only list in PostgreSQL. Basically, this is trivial: Create a table, and only ever INSERT into that table.
However, I would like to be able to read that list again, in the order it was created. How can I do this? Is a simple SELECT * FROM MyTable enough? If not, what do I sort by?
Rows in a relational database have no inherent sort order. The only way to get a guaranteed sort order is to use an order by.
You can either create an identity column that is incremented on every insert or a timestamp column that records the precise time a row was inserted (or do both).
e.g.
create table append_only
(
id bigint generated always as identity,
... other columns ...
created_at timestamp default clock_timestamp()
);
Then use that column for an order by. By having both, you can use the id column as a tie breaker when sorting by the timestamp in case two rows were inserted at exactly same microsecond.
You could create column with data type SERIAL(similiar to AUTOINCREMENT/SEQUENCE):
CREATE TABLE myTable(id SERIAL, ...)
SELECT * FROM myTable ORDER BY id;
I was trying to insert values from one table to another from two different databases.
My issue is I have two tables with a relation and the first table is having an identity column also.
eg table first(id, Name) - table second(id, address)
So now both the table exist with values in a db and i am trying to copy values from this db to another db.
So when I insert values from first db to second db the the first table will insert values for the Id column by itself so now I have to link that id to the second table.
How can I do that?
UPDATE using MSSQL server 2000
You can use #scope_identity immediately after your insert in SQL server 2000 which will give you the last id within the current scope but I'm not sure how that would work with bulk inserting of data
http://msdn.microsoft.com/en-us/library/ms190315.aspx
If this were SQL Server 2005 or later I would suggest using the output clause in your insert statement to retrieve the ids just inserted, but that was not available in SQL Server 2000.
If your data contains some column or series of columns which is unique other than the identity column, then you can query your first table based on that series of columns to get the ids and use that to populate your second table.
If the target tables were empty you could use SET IDENTITY_INSERT ON - this would allow to insert original values to identity columns, and you will not have to update referenced IDs. Of course if there is any existing ids that can overlap inserted ids - that is not the solution.
If names in first tables are unique, you could boild mapping between new and old ids and perform update something like this:
UPDATE S
SET S.id = F.id
FROM second S
INNER JOIN first_original FO ON FO.id = S.id
INNER JOIN first F ON F.name = FO.name
If names are not unique, then original ids should be saved in "first" in order to provide mapping between old and new ids. It can be temporary new column that can be deleted after ids in "second" will be updated.
Or as Rich Andrews said you could use #scope_identity, but in this case you will have to perform insert one by one - declare a cursor on source table, insert each record, get its new id and insert it into "second" table.
I am programming for iPhone and i am using SQLITE DB for my app.I have a situation where i want to insert records into the table,only if the records doesn't exist previously.Otherwise the records should not get inserted.
How can i do this?Please any body suggest me a suitable query for this.
Thank you one and all,
Looking at SQLite's INSERT page http://www.sqlite.org/lang_insert.html.
You can do it using the following syntax
INSERT OR IGNORE INTO tablename ....
Example
INSERT OR IGNORE INTO tablename(id, value, data) VALUES(2, 4562, 'Sample Data');
Note : You need to have a KEY on the table columns which uniquely identify a row. It is only if a duplicate KEY is tried to be inserted that INSERT OR IGNORE will not insert a new row.
In the above example if you have a KEY on id, then another row with id = 2 will not be inserted.
If you have a KEY only on id and value then a combination of id = 2 and value = 4562 will cause a new row not be inserted.
In short there must be a key to uniquely identify a ROW only then will the Database know there is a duplicate which SHOULD NOT Be allowed.
Otherwise if you do not have a KEY you would need to go the SELECT and then check if a row is already there, route. But here also whichever condition you are using on columns you can add them as a KEY to the table and simply use the INSERT OR IGNORE
In SQLite it is not possible to ALTER the table and add a constraint like UNIQUE or PRIMAY KEY. For that you need to recreate the table. Look at this FAQ on sqlite.org
http://sqlite.org/faq.html#q11
Hello Sankar what you can do is perform a select query with the record you wish to insert and then check the response via SQLite's SQLITE_NOTFOUND flag you can check whether that record already exists or not. If it doesn't exist you can insert it otherwise you skip inserting.
I hope this is helpful.
I need to duplicate selected rows with all the fields exactly same except ID ident int which is added automatically by SQL.
What is the best way to duplicate/clone record or records (up to 50)?
Is there any T-SQL functionality in MS SQL 2008 or do I need to select insert in stored procedures ?
The only way to accomplish what you want is by using Insert statements which enumerate every column except the identity column.
You can of course select multiple rows to be duplicated by using a Select statement in your Insert statements. However, I would assume that this will violate your business key (your other unique constraint on the table other than the surrogate key which you have right?) and require some other column to be altered as well.
Insert MyTable( ...
Select ...
From MyTable
Where ....
If it is a pure copy (minus the ID field) then the following will work (replace 'NameOfExistingTable' with the table you want to duplicate the rows from and optionally use the Where clause to limit the data that you wish to duplicate):
SELECT *
INTO #TempImportRowsTable
FROM (
SELECT *
FROM [NameOfExistingTable]
-- WHERE ID = 1
) AS createTable
-- If needed make other alterations to the temp table here
ALTER TABLE #TempImportRowsTable DROP COLUMN Id
INSERT INTO [NameOfExistingTable]
SELECT * FROM #TempImportRowsTable
DROP TABLE #TempImportRowsTable
If you're able to check the duplication condition as rows are inserted, you could put an INSERT trigger on the table. This would allow you to check the columns as they are inserted instead of having to select over the entire table.