I know there is a lot of question already asked and answered on this subject but they don't seem to fit my situation.
I have a distant sqlite database — DB server — and a local one — DB local containing photo album entries. DB local updates whenever needed from DB server. DB server has a primary key called identifier, which is stored in DB local to prevent duplicates, but DB local also has its own primary key column called id
If I need to create a new album on my phone I insert an entry in DB local with identifier set to -1 and when DB server will be reachable ask for a proper identifier.
My issue is : I do a lot of refresh and don't want to increment my primary key each time.
When I refresh DB local from DB server I would like to INSERT new albums, and UPDATE existing ones.
I read about the INSERT OR REPLACE statement but it would require my identifier column in DB local to be set as unique. Unfortunately I cannot do so since I can have multiple identifierset to -1.
Is there any way to perform an INSERT or UPDATE conditionally in a single request ?
Thanks !
EDIT : the update is done this way : the DB local is updated from DB server. DB local data is never pushed to DB server, the only way to add a new item is to call an API on the server which will create an empty entry on DB server and get its identifier. But since server is not always reachable (EDGE/3G) some entries in DB local have identifier set to -1. Once the API call have returned with the corresponding identifier we store it instead of -1 for the corresponding entry in DB local
Related
I am trying to delete a document from cosmos db using Logic App. The id exists in db, and I have provided the partition key as well. But still I get 404 error.
Can someone assist in adding a delete document function in logic app.
But the id exists in db
You need to pass the partition key value as the actual id instead of "id" which is the partition key path.
Change it to "fd39d4c4........." it should work then.
I'm trying to attach one database to another so that data from it can be used in queries.
I'm using
ATTACH DATABASE '{full url}' AS {database_name};
No errors actually occur, but when I run
PRAGMA database_list
Only the main database shows.
I found these limitations for ATTACH DATABASE that may or may not apply to your case:
The database names called main and temp are reserved names within your database connection and can not be used for attached databases.
The database name called main is reserved for the primary database and the database name called temp is reserved for the database that holds temporary tables.
Attached databases must use the same text encoding as the main database.
When the database connection is closed, the attached database will be automatically be detached.
I have an ASP.NET (C#) web application that connects to Informix 12.x database. The web application uses a database connection string with username and password. Users are given login accounts to use the web application and they can delete records in the database.
The database tables have "LastModifiedBy" which contains the user ID. Now, I need to implement auditing using database triggers. I need to capture what records were updated or deleted and who did it (i.e. logged in user) and save these in an audit table.
For the delete trigger, how can I capture the user ID of the logged in user and save this in the audit table?
The database user (available via the keyword USER) is always going to be the username associated with the shared database credentials. Your question is not very clear, but are you saying the existing LastModifiedBy attribute contains the named user or the database user? If it's the named user, I think you should probably look at your ASP.NET code to see how that gets passed into the UPDATE statement.
I'm no expert on ASP.NET, but assuming a single page request uses the same database connection throughout its processing cycle, then you could maintain a table keyed on the session ID, available via DBINFO('sessionid'), where you capture the named user at the top of the request, and then you have it available at any point throughout the process for inclusion in your audit. But if the web-server processes are using a pool of database connections and any statement could go to a different connection, even that won't work.
Ultimately, I don't think database triggers are the right solution here, not least because you'll have to write and maintain a trigger for every table in your application. If I was faced with this problem I would be more inclined to have a common Audit function within the web-app, where the named user is always available.
At the OP's request, a bit more detail. The Session ID is exactly the same concept as you see in SSMS - just a unique number that identifies the connection.
Imagine you have the following table and procedures:
CREATE TABLE session_user (
sessionid INTEGER NOT NULL,
username VARCHAR(20),
conn_date DATE,
PRIMARY KEY (sessionid)
);
CREATE PROCEDURE set_user(v_username VARCHAR(20))
UPDATE session_user SET username = v_username, conn_date = TODAY
WHERE sessionid = DBINFO('sessionid');
IF DBINFO('sqlca.sqlerrd2') = 0 THEN
INSERT INTO session_user VALUES (DBINFO('sessionid'), v_username, TODAY);
END PROCEDURE;
CREATE PROCEDURE get_user()
DEFINE v_username VARCHAR(20);
SELECT username INTO v_username
FROM session_user
WHERE sessionid = DBINFO('sessionid');
IF v_username IS NULL THEN
LET v_username = USER;
-- return system user if no record found in session_user table
END IF;
RETURN v_username;
END PROCEDURE;
NB: None of this code is tested, it's just to show the principle. I don't have an Informix instance to hand to test this on.
At the top of the request, however you execute your SQL, you would run:
EXECUTE PROCEDURE set_user($the_web_user);
Your triggers could then use get_user() wherever you want to capture that info. You'll get the actual web user if it's been recorded in the session_user table, otherwise the database user (which will be the shared database credentials if the triggering DML has come from the web-app, or the physically logged in user if the trigger is via a DB-Access session).
I still don't think this is a particularly maintainable solution - every table needs its own trigger(s). An OO audit method in the web-app would be a more DRY approach, or have a look at Informix's preexisting audit capabilities.
Note: the date field was included in the session_user table so you run a clean-up over it, because depending on how often new connections get created by the web-app, your session_user table could grow like topsy.
I tried the mention below query to stop duplicate before inserting data. It works fine with SQL database but its not working with access database. I want the same query to stop duplicate before inserting data to my access database. waiting for positive response. Thanks
IF NOT EXISTS (SELECT *
FROM dbo.Product
WHERE email = #email)
INSERT INTO dbo.Product(list of columns)
VALUES (list of values)
In both cases (SQL Server and MS Access) you should create a proper UNIQUE INDEX on the email column of the Product table.
For MS Access: http://office.microsoft.com/en-us/access-help/prevent-entry-of-duplicate-values-mdb-HP005187564.aspx
For SQL Server: http://technet.microsoft.com/en-us/library/ms189280.aspx
I have a table Product which have Quantity column, This table get updated thru .net application using Stored procedure based on flag variable. Now im having problem reported from user that even though the flag variable is not set table is getting updated with new values.
Now i need to isolated the cause for the issue.How will i check which update and through which application this table is getting modified. I have no idea about it.
What is the best approach to resolve this issue?
Assuming you are using SQL Server:
You can monitor calls to SQL Server using SQL Server Profiler. You can setup a filter to monitor queries affecting the Product table. The log will show what the query looked like, when the query was executed, the database user executing the query, the name of the application (if that is specified in the connection string) and a bunch of other things.