How can I create alias name to my database in SQL Server 2005?
For example: DB1 and its alias DB2, it's same DB, but with two names.
Or can I do replication, mirroring, syncing or anything other inside server from one DB to another?
You can do replication from one database to another database on the same machine. You can also copy data directly without having to create an alias. For instance if you had a table named Users in DB2 and a Users table in DB1 and they are the same schema you could easily just do
INSERT INTO DB1..Users
select * from DB2..Users
Now, a synonym would allow you to use a table from DB2 as if it was a table in DB1 so for instance if you have a table named Products in DB2 you could do
use DB1
GO
CREATE SYNONYM [dbo].[Products] FOR [DB2].[dbo].[Products]
GO
-- Now the following would give you the same result
select * from DB2..Products
select * from Products
For more information on synonyms see here
I want to write a procedure in SQL anywhere which can check if a local temporary table exists and if it does use it. I do not want to drop the table. I have already found a way to drop local temporary table which is:
DROP TABLE IF EXISTS t;
I have also tried following:
I created a local temporary table TEMP_TABLE. Then I tried to run this query:
select object_id('tempdb..TEMP_TABLE')
This just gives me NULL. But if I try
select * from TEMP_TABLE
it works perfectly fine.
So can anyone please help me find a way to check if the local temporary table exists in sql anywhere.
I'm not sure what version of Sybase you have but this works in Sybase 11 so I can imagine it will work in any version up too:
Begin
Create local Temporary table TEMP_TABLE (column1 int); //Create temp table
// any other code needed to be executed if table did not exist
Exception when others then
// Code to be executed when table does exist
end;
This is basically a try..catch for sybase. If the Temp Table exists it will throw an exception, in the exception you can run the code you want to knowing that the table already exists.
In one query you are referring database and in other you are not, try below two queries.
select object_id('tempdb..TEMP_TABLE')
select * from tempdb..TEMP_TABLE
select object_id('TEMP_TABLE')
select * from TEMP_TABLE
If I create a temporary table using # sign:
SELECT * INTO #temp FROM dbo.table
Where is this table located? I can't find this from tempdb.
Those tables are created in your tempDB - but the table name might not be exactly as you defined.
In my case, I get:
#temp______________________________000000000003
Try this:
SELECT * INTO #temp FROM dbo.table
SELECT * FROM tempdb.sys.tables
You should see an entry for that temp table you've just created....
When you declare a temporary table, SQL Sever adds some additional characters on its name in order to provide a unique system name for it and then it stores it in tempDB in the sysobjects table. Even though you can query the temporary table with its logical name, internally is known with the exact name SQL Server has set.
How are you looking for them?
If you do a select you'll get the data.
But the table is only available in the session, just for the user who created it (you can have global temp tables).
They are stored in temp db.
Local temp tables can be created using hash (#) sign prior to table name.
They are visible only in current connection. When connection is dropped its scope ends as well.
It is possible to create and use local temp table with the same name simultaneously in two different connections.
Read More
http://sqlnetcode.blogspot.com/2011/11/there-is-already-object-named-temp-in.html
I suspect this issue rose from the fact that if you don't right click and refresh the 'Temporary Tables' folder, SSMS will not show you the temp table immediately.
I would like to create a temporary table in a Oracle database
something like
Declare table #table (int id)
In SQL server
And then populate it with a select statement
Is it possible?
Thanks
Yep, Oracle has temporary tables. Here is a link to an AskTom article describing them and here is the official oracle CREATE TABLE documentation.
However, in Oracle, only the data in a temporary table is temporary. The table is a regular object visible to other sessions. It is a bad practice to frequently create and drop temporary tables in Oracle.
CREATE GLOBAL TEMPORARY TABLE today_sales(order_id NUMBER)
ON COMMIT PRESERVE ROWS;
Oracle 18c added private temporary tables, which are single-session in-memory objects. See the documentation for more details. Private temporary tables can be dynamically created and dropped.
CREATE PRIVATE TEMPORARY TABLE ora$ptt_today_sales AS
SELECT * FROM orders WHERE order_date = SYSDATE;
Temporary tables can be useful but they are commonly abused in Oracle. They can often be avoided by combining multiple steps into a single SQL statement using inline views.
Just a tip.. Temporary tables in Oracle are different to SQL Server. You create it ONCE and only ONCE, not every session. The rows you insert into it are visible only to your session, and are automatically deleted (i.e., TRUNCATE, not DROP) when you end you session ( or end of the transaction, depending on which "ON COMMIT" clause you use).
CREATE GLOBAL TEMPORARY TABLE Table_name
(startdate DATE,
enddate DATE,
class CHAR(20))
ON COMMIT DELETE ROWS;
CREATE TABLE table_temp_list_objects AS
SELECT o.owner, o.object_name FROM sys.all_objects o WHERE o.object_type ='TABLE';
I know the statement:
create table xyz_new as select * from xyz;
Which copies the structure and the data, but what if I just want the structure?
Just use a where clause that won't select any rows:
create table xyz_new as select * from xyz where 1=0;
Limitations
The following things will not be copied to the new table:
sequences
triggers
indexes
some constraints may not be copied
materialized view logs
This also does not handle partitions
I used the method that you accepted a lot, but as someone pointed out it doesn't duplicate constraints (except for NOT NULL, I think).
A more advanced method if you want to duplicate the full structure is:
SET LONG 5000
SELECT dbms_metadata.get_ddl( 'TABLE', 'MY_TABLE_NAME' ) FROM DUAL;
This will give you the full create statement text which you can modify as you wish for creating the new table. You would have to change the names of the table and all constraints of course.
(You could also do this in older versions using EXP/IMP, but it's much easier now.)
Edited to add
If the table you are after is in a different schema:
SELECT dbms_metadata.get_ddl( 'TABLE', 'MY_TABLE_NAME', 'OTHER_SCHEMA_NAME' ) FROM DUAL;
create table xyz_new as select * from xyz where rownum = -1;
To avoid iterate again and again and insert nothing based on the condition where 1=2
Using sql developer select the table and click on the DDL tab
You can use that code to create a new table with no data when you run it in a sql worksheet
sqldeveloper is a free to use app from oracle.
If the table has sequences or triggers the ddl will sometimes generate those for you too. You just have to be careful what order you make them in and know when to turn the triggers on or off.
You can do this
Create table New_table as select * from Old_table where 1=2 ;
but be careful
The table you create does not have any Index, PK and so on like the old_table.
DECLARE
l_ddl VARCHAR2 (32767);
BEGIN
l_ddl := REPLACE (
REPLACE (
DBMS_LOB.SUBSTR (DBMS_METADATA.get_ddl ('TABLE', 'ACTIVITY_LOG', 'OLDSCHEMA'))
, q'["OLDSCHEMA"]'
, q'["NEWSCHEMA"]'
)
, q'["OLDTABLSPACE"]'
, q'["NEWTABLESPACE"]'
);
EXECUTE IMMEDIATE l_ddl;
END;
Simply write a query like:
create table new_table as select * from old_table where 1=2;
where new_table is the name of the new table that you want to create and old_table is the name of the existing table whose structure you want to copy, this will copy only structure.
SELECT * INTO newtable
FROM oldtable
WHERE 1 = 0;
Create a new, empty table using the schema of another. Just add a WHERE clause that causes the query to return no data:
WHERE 1 = 0 or similar false conditions work, but I dislike how they look. Marginally cleaner code for Oracle 12c+ IMHO is
CREATE TABLE bar AS
SELECT *
FROM foo
FETCH FIRST 0 ROWS ONLY;
Same limitations apply: only column definitions and their nullability are copied into a new table.
If one needs to create a table (with an empty structure) just to EXCHANGE PARTITION, it is best to use the "..FOR EXCHANGE.." clause. It's available only from Oracle version 12.2 onwards though.
CREATE TABLE t1_temp FOR EXCHANGE WITH TABLE t1;
This addresses 'ORA-14097' during the 'exchange partition' seamlessly if table structures are not exactly copied by normal CTAS operation. I have seen Oracle missing some of the "DEFAULT" column and "HIDDEN" columns definitions from the original table.
ORA-14097: column type or size mismatch in ALTER TABLE EXCHANGE
PARTITION
See this for further read...
you can also do a
create table abc_new as select * from abc;
then truncate the table abc_new. Hope this will suffice your requirement.
Using pl/sql developer you can right click on the table_name either in the sql workspace or in the object explorer, than click on "view" and than click "view sql" which generates the sql script to create the table along with all the constraints, indexes, partitions etc..
Next you run the script using the new_table_name
copy without table data
create table <target_table> as select * from <source_table> where 1=2;
copy with table data
create table <target_table> as select * from <source_table>;
In other way you can get ddl of table creation from command listed below, and execute the creation.
SELECT DBMS_METADATA.GET_DDL('TYPE','OBJECT_NAME','DATA_BASE_USER') TEXT FROM DUAL
TYPE is TABLE,PROCEDURE etc.
With this command you can get majority of ddl from database objects.
Create table target_table
As
Select *
from source_table
where 1=2;
Source_table is the table u wanna copy the structure of.
create table xyz_new as select * from xyz;
-- This will create table and copy all data.
delete from xyz_new;
-- This will have same table structure but all data copied will be deleted.
If you want to overcome the limitations specified by answer:
How can I create a copy of an Oracle table without copying the data?
The task above can be completed in two simple steps.
STEP 1:
CREATE table new_table_name AS(Select * from old_table_name);
The query above creates a duplicate of a table (with contents as well).
To get the structure, delete the contents of the table using.
STEP 2:
DELETE * FROM new_table_name.
Hope this solves your problem. And thanks to the earlier posts. Gave me a lot of insight.