I am relatively new to databases and SQL, and I am not clear on how or whether transactions may relate to a problem that I am trying to solve. I want to be able to temporarily set a value in a database table, run some query, and then clear out the value that was set, and I don't want any operations outside of the transaction to be able to see or alter the temporary value that was set.
The reason I am doing this is so that I can create predefined views that query certain data depending on variables such as the current user's id. In order for the predefined view to have access to the current user's id, I would save the id into a special table just before querying the view, then delete the id immediately afterward. I don't want to worry about some other user overwriting the current user's id while the transaction is in process. Is this a proper use for a transaction?
I am using H2 if that makes a difference.
SET #tempVar=value;
I don't know if you really need to go through the pain of creating a temp table and setting the value. This seems far simpler.
You can then do - SELECT * FROM TABLE_NAME WHERE COLUMN=#tempVar;
I think you want a Procedure or Function. Both can take a parameter as input.
ex.
CREATE PROCEDURE pr_emp
(
#input INT
)
AS
SELECT *
FROM myTable
WHERE emp_id = #input
ex.
CREATE FUNCTION v_empid (#input INT)
RETURNS TABLE
AS
RETURN
SELECT * FROM myTABLE WHERE emp_id = #input;
These could let you to access information for an empid. For example:
SELECT * FROM v_empid(32)
I am new to oracle. I would like to ask if there exist one single command that could copy table a to table b such that table b would have the same data, same structure and same access priviledge as table a? I would like to make a duplicate of a table which contain the same behavior.
Someone please correct me if I am wrong, but I don't think you can copy it with privileges/indexes as it is. That might be becasuse you need to give a new name for the index,primary key etc, and the database will not know what name needs to be given to these. So you can do this.
Run this to get the DDL of the table you want and then replace it with new table name. (my source table is TZ_TEST and I will create TZ_TEST_NEW. (Thanks to this answer for get_ddl command)
select replace(
(SELECT dbms_metadata.get_ddl( 'TABLE', 'TZ_TEST' ) FROM DUAL),
'TZ_TEST',
'TZ_TEST_NEW')
from dual
Execute the DDL
Use this to get grant permissions
select replace(
(select DBMS_METADATA.GET_DEPENDENT_DDL('OBJECT_GRANT','TZ_TEST') FROM DUAL),
'TZ_TEST',
'TZ_TEST_NEW') from dual
Similarly use DBMS_METADATA to get constraints/index etc. Execute these statmetns.
Insert data
insert into TZ_TEST_NEW
select * from TZ_TEST
Please remember that if you have an auto generated primary key, then while inserting data, you need to exclude that column from insert and select statments.
Anyone please feel free to add if I missed something.
Also we can create a procedure which can so all this but you need to be careful with all the steps. So once you do it couple of times and it works, we can create a procedure for it.
If you are using TOAD for Oracle, then select the table name and press F4. Then select script tab in the describe window.
This will generate the table script. You just need to use Search/Replace to change the table name and execute the script.
The newly created table will contain the same behavior.
I would do it in two steps:
Use CTAS i.e. create table as select .. to first create a copy of the table with new name with the data. You could also use PARALLEL and NOLOGGING feature to increase the performance.
For example,
create table t parallel 4 nologging as select * from emp;
Get the associated structures like indexes, constraints etc. using DBMS_METADATA.GET_DEPENDENT_DDL and execute it. But, you need to first replace the table_name to your new table_name as you have created in step 1.
CTAS would be much faster than traditional insert.
I have a table 'Goods' with different information about goods (name, price, etc). I need to create a view at the same scheme as table 'Goods' has. But the view must be empty. And when user adds new good to the view it is saved in table 'Goods', but the view remains empty when user opens it next time. So main idea is not to show existing data to the user which has access to the view.
Assuming your on a database system that supports a concept like SQL Server's CHECK OPTION, and you're allowed to create a view that doesn't have that option set, you should be fine:
create table T (ID int not null)
go
create view V
as
select * from T where 1=0
go
select * from V
go
insert into V(ID) values (10)
go
select * from V
go
select * from T
The two selects from V return 0 rows. The select from T returns one row:
ID
----
10
CHECK OPTION:
Forces all data modification statements executed against the view to follow the criteria set within select_statement. When a row is modified through a view, the WITH CHECK OPTION makes sure the data remains visible through the view after the modification is committed.
And you want the opposite - you want to allow data modifications performed through the view to create rows which are invisible through the view.
Create table Goods1 with "insert trigger" on it which make insert into Goods and delete from Goods1
As far as I know this isn't possible. The whole point of a view is that it is a view to a table or grouping of tables, ie. it must show the data that matches the view.
http://www.w3schools.com/sql/sql_view.asp
What you could do is create another table called GoodsView and add a trigger to it to INSERT into Goods table and DELETE from GoodsView afterwards.
http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=%2Fsqlp%2Frbafysqltrig.htm
How to change column order in a table using SQL query in SQL Server 2005?
I want to rearrange column order in a table using SQL query.
You cannot. The column order is just a "cosmetic" thing we humans care about - to SQL Server, it's almost always absolutely irrelevant.
What SQL Server Management Studio does in the background when you change column order there is recreating the table from scratch with a new CREATE TABLE command, copying over the data from the old table, and then dropping it.
There is no SQL command to define the column ordering.
You have to explicitly list the fields in the order you want them to be returned instead of using * for the 'default' order.
original query:
select * from foobar
returns
foo bar
--- ---
1 2
now write
select bar, foo from foobar
bar foo
--- ---
2 1
according to https://learn.microsoft.com/en-us/sql/relational-databases/tables/change-column-order-in-a-table
This task is not supported using Transact-SQL statements.
Well, it can be done, using create/ copy / drop/ rename, as answered by komma8.komma1
Or you can use SQL Server Management Studio
In Object Explorer, right-click the table with columns you want to reorder and click Design (Modify in ver. 2005 SP1 or earlier)
Select the box to the left of the column name that you want to reorder. (You can select multiple columns by holding the [shift] or
the [ctrl] keys on your keyboard.)
Drag the column(s) to another location within the table.
Then click save. This method actually drops and recreates the table, so some errors might occur.
If Change Tracking option is enabled for the database and the table, you shouldn't use this method.
If it is disabled, the Prevent saving changes that require the table re-creation option should be cleared in Tools menu > Options > Designers, otherwise "Saving changes is not permitted" error will occur.
Disabling the Prevent saving changes that require the table re-creation option is strongly advised against by Microsoft, as it leads to the existing change tracking information being deleted when the table is re-created, so you should never disable this option if Change Tracking is enabled!
Problems may also arise during primary and foreign key creation.
If any of the above errors occurs, saving fails which leaves you with the original column order.
In SQLServer Management Studio:
Tools -> Options -> Designers -> Table and Database Designers
Unselect 'Prevent saving changes that require table re-creation'.
Then:
right click the table you want to re-order the columns for.
click 'Design'.
Drag the columns to the order you want.
finally, click save.
SQLServer Management studio will drop the table and recreate it using the data.
This is similar to the question on ordering the records in the result of a query .. and typically no one likes the formally correct answer ;-)
So here it goes:
as per SQL standard, the columns in a table are not "ordered"
as a result, a select * does not force the columns to be returned in a particular order
typically, each RDBMS has a kind of "default" order (usually the order that the columns were added to the table, either in the create table' or in thealter table add ` statements
therefore, if you rely on the order of columns (because you are using the results of a query to poulate some other datastructure from the position of the columns), explicitly list the columns in the order you want them.
You can of course change the order of the columns in a sql statement. However if you want to abstract tables' physical column order, you can create a view. i.e
CREATE TABLE myTable(
a int NULL,
b varchar(50) NULL,
c datetime NULL
);
CREATE VIEW vw_myTable
AS
SELECT c, a, b
FROM myTable;
select * from myTable;
a b c
- - -
select * from vw_myTable
c a b
- - -
You can do it by creating a new table, copy all the data over, drop the old table, then renaming the new one to replace the old one.
You could also add new columns to the table, copy the column by column data over, drop the old columns, then rename new columns to match the old ones. A simple example below:
http://sqlfiddle.com/#!3/67af4/1
CREATE TABLE TestTable (
Column1 INT,
Column2 VARCHAR(255)
);
GO
insert into TestTable values(1, 'Test1');
insert into TestTable values(2, 'Test2');
GO
select * from TestTable;
GO
ALTER TABLE TestTable ADD Column2_NEW VARCHAR(255);
ALTER TABLE TestTable ADD Column1_NEW INT;
GO
update TestTable
set Column1_NEW = Column1,
Column2_NEW = Column2;
GO
ALTER TABLE TestTable DROP COLUMN Column1;
ALTER TABLE TestTable DROP COLUMN Column2;
GO
sp_rename 'TestTable.Column1_NEW', 'Column1', 'COLUMN';
GO
sp_rename 'TestTable.Column2_NEW', 'Column2', 'COLUMN';
GO
select * from TestTable;
GO
In SQLServer Management Studio:
Tools -> Options -> Designers -> Table and Database Designers
Unselect Prevent saving changes that require table re-creation.
Now you can reorder the table.
Sql server internally build the script. It create a temporary table with new changes and copy the data and drop current table then recreate the table insert from temp table. I find it from "Generate Change script" option ssms 2014. Script like this. From Here: How to change column order in a table using sql query
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_emps
(
id int NULL,
ename varchar(20) NULL
) ON [PRIMARY]
GO
ALTER TABLE dbo.Tmp_emps SET (LOCK_ESCALATION = TABLE)
GO
IF EXISTS(SELECT * FROM dbo.emps)
EXEC('INSERT INTO dbo.Tmp_emps (id, ename)
SELECT id, ename FROM dbo.emps WITH (HOLDLOCK TABLOCKX)')
GO
DROP TABLE dbo.emps
GO
EXECUTE sp_rename N'dbo.Tmp_emps', N'emps', 'OBJECT'
GO
COMMIT
If your table has enough columns then you can try this. First create a new table with preferred order of columns.
create table new as select column1,column2,column3,....columnN from table_name;
Now drop the table using drop command
drop table table_name;
now rename the newly created table to your old table name.
rename new to table_name;
now select the table, you have your columns rearranged as you preferred before.
select * from table_name;
Not sure if still relevant, but SSMS can generate a change scripts for this.
Re-order (drag the column) the table in Designer View
Click on 'Generate Change Script'
The generated script contains the script which does the following:
Create a temporary table
Adds the constraints, relationships and triggers from original table to temporary table
Drop original table
Rename temporary table to original table name
If you have not yet added any data into your table yet, there is one way to move the columns around.
Try this:
In SSMS, click Tools > Options > Designers > Table and Database Designers > Uncheck the box next to Prevent saving changes that require table re-creation > Click OK.
In the object tree, right-click on your table and select Design > in the thin column to the left of the Column Name column, you can click and drag the columns around to wherever you want them. When you're done, just go to close the Design tab and SSMS will ask you if you want to save your changes, click OK.
Optional:
3. Re-enable the checkbox for the option from Step 1 to re-secure your table.
Hope this helps someone!
Credit goes to Microsoft:
https://learn.microsoft.com/en-us/troubleshoot/sql/ssms/error-when-you-save-table#more-information
At the end of the day, you simply cannot do this in MS SQL. I recently created tables on the go (application startup) using a stored Procedure that reads from a lookup table. When I created a view that combined these with another table I had manually created earlier one (same schema, with data), It failed - simply because I was using ''Select * UNION Select * ' for the view. At the same time, if I use only those created through the stored procedure, I am successful.
In conclusion: If there is any application which depends on the order of column it is really not good programming and will for sure create problems in the future. Columns should 'feel' free to be anywhere and be used for any data process (INSERT, UPDATE, SELECT).
You can achieve it with these steps:
remove all foreign keys and primary key of the original table.
rename the original table.
using CTAS create the original table in the order you want.
drop the old table.
apply all constraints back to the original table
If the columns to be reordered have recently been created and are empty, then the columns can be deleted and re-added in the correct order.
This happened to me, extending a database manually to add new functionality, and I had missed a column out, and when I added it, the sequence was incorrect.
After finding no adequate solution here I simply corrected the table using the following kind of commands.
ALTER TABLE tablename DROP COLUMN columnname;
ALTER TABLE tablename ADD columnname columntype;
Note: only do this if you don't have data in the columns you are dropping.
People have said that column order does not matter. I regularly use SQL Server Management Studio "generate scripts" to create a text version of a database's schema. To effectively version control these scripts (git) and to compare them (WinMerge), it is imperative that the output from compatible databases is the same, and the differences highlighted are genuine database differences.
Column order does matter; but just to some people, not to everyone!
Use
SELECT * FROM TABLE1
which displays the default column order of the table.
If you want to change the order of the columns.
Specify the column name to display correspondingly
SELECT COLUMN1, COLUMN5, COLUMN4, COLUMN3, COULMN2 FROM TABLE1
you can use indexing.. After indexing, if select * from XXXX results should be as per the index, But only result set.. not structrue of Table
In order to have a specific column order You need to select column by column in the order You wish.
Selection order dictates how columns will be ordered in output.
Try this command:
alter table students modify age int(5) first;
This will change the position of age to the first position.
You can change this using SQL query. Here is sql query to change the sequence of column.
ALTER TABLE table name
CHANGE COLUMN `column1` `column1` INT(11) NOT NULL COMMENT '' AFTER `column2`;
alter table name modify columnname int(5) first;
will bring the column to first
alter table name modify columnname int(5) after (tablename);
This worked for me on Oracle DB:
select column1, column2, t.* from table t
Example: Change position of field_priority after field_price in table status.
ALTER TABLE `status` CHANGE `priority` `priority` INT(11) NULL DEFAULT NULL AFTER `price`;
Basically I have a two databases on SQL Server 2005.
I want to take the table data from one database and copy it to another database's table.
I tried this:
SELECT * INTO dbo.DB1.TempTable FROM dbo.DB2.TempTable
This didn't work.
I don't want to use a restore to avoid data loss...
Any ideas?
SELECT ... INTO creates a new table. You'll need to use INSERT. Also, you have the database and owner names reversed.
INSERT INTO DB1.dbo.TempTable
SELECT * FROM DB2.dbo.TempTable
SELECT * INTO requires that the destination table not exist.
Try this.
INSERT INTO db1.dbo.TempTable
(List of columns here)
SELECT (Same list of columns here)
FROM db2.dbo.TempTable
It's db1.dbo.TempTable and db2.dbo.TempTable
The four-part naming scheme goes:
ServerName.DatabaseName.Schema.Object
Hard to say without any idea what you mean by "it didn't work." There are a whole lot of things that can go wrong and any advice we give in troubleshooting one of those paths may lead you further and further from finding a solution, which may be really simple.
Here's a something I would look for though,
Identity Insert must be on on the table you are importing into if that table contains an identity field and you are manually supplying it. Identity Insert can also only be enabled for 1 table at a time in a database, so you must remember to enable it for the table, then disable it immediately after you are done importing.
Also, try listing out all your fields
INSERT INTO db1.user.MyTable (Col1, Col2, Col3)
SELECT Col1, COl2, Col3 FROM db2.user.MyTable
We can three part naming like database_name..object_name
The below query will create the table into our database(with out constraints)
SELECT *
INTO DestinationDB..MyDestinationTable
FROM SourceDB..MySourceTable
Alternatively you could:
INSERT INTO DestinationDB..MyDestinationTable
SELECT * FROM SourceDB..MySourceTable
If your destination table exists and is empty.
Don't forget to insert SET IDENTITY_INSERT MobileApplication1 ON to the top, else you will get an error. This is for SQL Server
SET IDENTITY_INSERT MOB.MobileApplication1 ON
INSERT INTO [SERVER1].DB.MOB.MobileApplication1 m
(m.MobileApplicationDetailId,
m.MobilePlatformId)
SELECT ma.MobileApplicationId,
ma.MobilePlatformId
FROM [SERVER2].DB.MOB.MobileApplication2 ma
Im prefer this one.
INSERT INTO 'DB_NAME'
(SELECT * from 'DB_NAME#DB_LINK')
MINUS
(SELECT * FROM 'DB_NAME');
Which means will insert whatsoever that not included on DB_NAME but included at DB_NAME#DB_LINK. Hope this help.
INSERT INTO DB1.dbo.TempTable
SELECT * FROM DB2.dbo.TempTable
If we use this query it will return Primary key error.... So better to choose which columns need to be moved, like
INSERT INTO db1.dbo.TempTable // (List of columns here)
SELECT (Same list of columns here)
FROM db2.dbo.TempTable
Try this
INSERT INTO dbo.DB1.TempTable
(COLUMNS)
SELECT COLUMNS_IN_SAME_ORDER FROM dbo.DB2.TempTable
This will only fail if an item in dbo.DB2.TempTable is in already in dbo.DB1.TempTable.
This works successfully.
INSERT INTO DestinationDB.dbo.DestinationTable (col1,col1)
SELECT Src-col1,Src-col2 FROM SourceDB.dbo.SourceTable
You can copy one table to other db table even with some additional columns.
insert into [SchoolDb1].[dbo].Student(Col1, Col2,Col3, CreationTime, IsDeleted)
select Col1, Col2,Col3,,getdate(),0 from [SchoolDb2].[dbo].Student
These are additional columns: (CreationTime is datatime and IsDeleted is boolean)
select * from DBA1.TABLENAMEA;
create table TABLENAMEA as (select * from DBA1.TABLENAMEA);
These manual way provides more flexibility, but at the same time, works for table whose size is smaller to few thousands.
Do select * from <table name> from DB, once whole table is displayed, scroll till it's bottom.
Right click and do Export table as Insert statement, provide the name of the destination table and export the table as .sql file.
Use any text editor to further do regular find and replace operation to include more column names etc.
Use the INSERT statement in destination DB.