I have 4 tables:
Table A:
LogID (unique identifier),
UserID (bigint),
LogDate (date/time),
LogEventID (int),
IPID (varchar(36)),
UserAgentID (varchar(36))
Table B:
IPID (unique identifier),
IPAddress (varchar(255))
Table C:
UserAgentID (unique identifier),
UserAgent (varchar(255))
Table D:
LogEventID (int),
LogEvent (varchar(255))
I am trying to write the to Table A but need to check Table B, Table C and Table D contain data so I can link them. If they don’t contain any data, I would need to create some. Some of the tables may contain data, sometimes none of them may.
Pretty much everything, really struggling
first, you do a insert into table B, C, D WHERE NOT EXISTS
example
INSERT INTO TableB (IPID, IPAddress)
SELECT #IPPD, #IPAddress
WHERE NOT EXISTS
(
SELECT *
FROM TableB x
WHERE x.IPID = #IPID
)
then you insert into table A
INSERT INTO TableA ( . . . )
SELECT . . .
SQL Server doesn't let you modify multiple tables in a single statement, so you cannot do this with a single statement.
What can you do?
You can wrap the multiple statements in a single transaction, if your goal is to modify the database only once.
You can write the multiple statements in stored procedure.
What you really probably want is a view with insert triggers on the view. You can define a view that is the join of the tables with the values from the reference tables. An insert trigger can then check if the values exist and replace them with the appropriate ids. Or, insert into the appropriate table.
The third option does exactly what you want. I find that it is a bit of trouble to maintain triggers, so for an application, I would prefer wrapping the logic in a stored procedure.
Related
I want to insert a new record if the record is not present in the table
For that I am using below query in Teradata
INSERT INTO sample(id, name) VALUES('12','rao')
WHERE NOT EXISTS (SELECT id FROM sample WHERE id = '12');
When I execute the above query I am getting below error.
WHERE NOT EXISTS
Failure 3706 Syntax error: expected something between ')' and the 'WHERE' keyword.
Can anyone help with the above issue. It will be very helpful.
You can use INSERT INTO ... SELECT ... as follows:
INSERT INTO sample(id,name)
select '12','rao'
WHERE NOT EXISTS (SELECT id FROM sample WHERE id = '12');
You can also create the primary/unique key on id column to avoid inserting duplicate data in id column.
I would advise writing the query as:
INSERT INTO sample (id, name)
SELECT id, name
FROM (SELECT 12 as id, 'rao' as name) x
WHERE NOT EXISTS (SELECT 1 FROM sample s WHERE s.id = x.id);
This means that you do not need to repeat the constant value -- such repetition can be a cause of errors in queries. Note that I removed the single quotes. id looks like a number so treat it as a number.
The uniqueness of ids is usually handled using a unique constraint or index:
alter table sample add constraint unq_sample_id unique (id);
This makes sure that the database ensures uniqueness. Your approach can fail if two inserts are run at the same time with the same id. An attempt to insert a duplicates returns an error (which the exists can then avoid).
In practice, id columns are usually generated automatically by the database. So the create table statement would look more like:
id integer generated by default as identity
And the insert would look like:
insert into sample (name)
values (name);
If id is the Primary Index of the table you can use MERGE:
merge into sample as tgt
using VALUES('12','rao') as src (id, name)
on src.id = tgt.id
when not matched
then insert (src.id,src.name)
I want to insert a dataset in a table. The insert query should insert the data into two tables.
Here are the tables:
Table A:
ID, customerId, ..[some other columns]...
Table B:
customerId, name
The query should insert into both Table A and Table B. How can I insert values into Table B with the relation customerId?
EDIT: the DBMS is sqlite.
The defintions:
Adaption:
id -> integer not null
customerId -> integer not null
some text columns....
Customer:
customerId -> integer not null
name -> text not null
Im not sure, I fully understand your problem, but i suggest you to see into the technology called :
Transaction (https://en.wikipedia.org/wiki/Database_transaction)
Technically that will be still two (or more) insert queries, but it will let you keep the integrity of your dataset. Transactions are implemented in the most DBMS.
In Table A i have many fields like referenceid, amount, timestamp, remarks, status, balancebefore, balanceafter, frmsisdn, tomsisdn, id etc etc
I want to create a new table, Table B based of Table A(with column names, datatypes etc etc) but i only need specific columns that are in table A.
I tried select * into TableB from TableA where 1 = 2 but it says ORA-00905: missing keyword. I am using TOAD.
thank you
In Oracle, the correct syntax is create table as. SELECT INTO is used primarily in SQL Server and Sybase.
create table tableb as
select . . .
from tableA;
Only include the where clause if you don't actually want to insert any rows.
In MySQL the syntax is the same as Oracle's (see here).
Notice that the new table does not contain any constraints from the original table (indexes, keys, etc.)
I have 2 tables. The following are just a stripped down version of these tables.
TableA
Id <pk> incrementing
Name varchar(50)
TableB
TableAId <pk> non incrementing
Name varchar(50)
Now these tables have a relationship to each other.
Scenario
User 1 comes to my site and does some actions(in this case adds rows to Table A). So I use a SqlBulkCopy all this data in Table A.
However I need to add the data also to Table B but I don't know the newly created Id's from Table A as SQLBulkCopy won't return these.
So I am thinking of having a stored procedure that finds all the id's that don't exist in Table B and then insert them in.
INSERT INTO TableB (TableAId , Name)
SELECT Id,Name FROM TableA as tableA
WHERE not exists( ...)
However this comes with a problem. A user at any time can delete something from TableB so if a user deletes say a row and then another user comes around or even the same user comes around and does something to Table A my stored procedure will bring back that deleted row in Table B. Since it will still exist in Table A but not Table B and thus satisfy the stored procedure condition.
So is there a better way of dealing with two tables that need to be updated when using bulk insert?
SQLBulkCopy complicates this so I'd consider using a staging table and an OUTPUT clause
Example, in a mixture of client pseudo code and SQL
create SQLConnection
Create #temptable
Bulkcopy to #temptable
Call proc on same SQLConnection
proc:
INSERT tableA (..)
OUTPUT INSERTED.key, .. INTO TableB
SELECT .. FROM #temptable
close connection
Notes:
temptable will be local to the connection and be isolated
the writes to A and B will be atomic
overlapping or later writes don't care about what happens later to A and B
emphasising the last point, A and B will only ever be populated from the set of rows in #temptable
Alternative:
Add another column to A and B called sessionid and use that to identify row batches.
One option would be to use SQL Servers output clause:
INSERT YourTable (name)
OUTPUT INSERTED.*
VALUES ('NewName')
This will return the id, name of the inserted rows to the client, so you can use them in the insert operation for the second table.
Just as an alternative solution you could use database triggers to update the second table.
Is there a way i can do multiple inserts into one table using a condition?
i have a list of subscribers in tbl_subscribers. i have an update on productX so i would like everyone who is subscribes to productX to get a notification. The user_notification table is id PK, user_id, notification_id. The two values i need is product_id (productX) which allows me to find a list of subscribers in tbl_subscribers and the notification_id to insert into the user_notification table.
How can i do this insert using one query? I see you can do a select statement in sqlite http://www.sqlite.org/lang_insert.html but i cannot wrap my head around how i may do this nor seen an example.
I believe you're looking from INSERT SELECT as outlined here:
http://www.1keydata.com/sql/sqlinsert.html
The second type of INSERT INTO allows
us to insert multiple rows into a
table. Unlike the previous example,
where we insert a single row by
specifying its values for all columns,
we now use a SELECT statement to
specify the data that we want to
insert into the table. If you are
thinking whether this means that you
are using information from another
table, you are correct. The syntax is
as follows:
INSERT INTO "table1" ("column1", "column2", ...)
SELECT "column3", "column4", ... FROM "table2"
insert into user_notification(user_id, notification_id)
select s.user_id, #notification_id
from tbl_subscriber s
where s.product_id = #productX