Get generated key from column organized table in DB2 Warehouse - sql

I am not able to get generated key from column organized table from an INSERT SQL statement run against IBM DB2 warehouse. I am using Java and JDBC driver. Everything works fine - I am able to connect to DB, create tables, insert data, I am just not able to get a generated key if it is generated in column organized table. Note that row organized tables work fine and return the key properly.
Consider a table:
CREATE TABLE users (
id INTEGER not null GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 1),
username VARCHAR(16),
PRIMARY KEY (id)
);
If this is row organized table I am able to get the generated key fine by using:
PreparedStatement pr = connection.prepareStatement("INSERT INTO users(username) VALUES(?)", PreparedStatement.RETURN_GENERATED_KEYS);
However, If this is column organized table the PreparedStatemnt creation fails with an error:
com.ibm.db2.jcc.am.SqlSyntaxErrorException: DB2 SQL Error: SQLCODE=-1667, SQLSTATE=42858, SQLERRMC=BLUADMIN.USERS;ORGANIZE BY COLUMN;FINAL|NEW|OLD TABLE, DRIVER=4.25.13
Even if I specify columns I want to get returned like so:
PreparedStatement pr = connection.prepareStatement("INSERT INTO users(username) VALUES(?)", new String[]{"id","username"});
pr.setString(1, "test");
pr.executeUpdate();
I get
com.ibm.db2.jcc.am.SqlSyntaxErrorException: DB2 SQL Error: SQLCODE=-1667, SQLSTATE=42858, SQLERRMC=BLUADMIN.USERS;ORGANIZE BY COLUMN;FINAL|NEW|OLD TABLE, DRIVER=4.25.13
on line pr.executeUpdate();.
Does this mean that it is not possible to get generated key from column organized table from the INSERT statement in DB2 Warehouse?


Currently shipping versions v11.1.x and V11.5.x will throw SQL1667N when the query sent to Db2 uses 'FINAL TABLE' or 'OLD TABLE', or 'NEW TABLE' clauses for a column organized table.
When you use the jdbc syntax PreparedStatement.RETURN_GENERATED_KEYS, this syntax may be used under the covers.
Currently those clauses are not supported (i.e. will cause the exception to be thrown) for ORGANIZE BY COLUMN tables. There are other restrictions on column organized tables that you should be aware of before using them.
You can workaround this by creating your tables explicitly with the ORGANIZE BY ROW clause.


Have you tried actually selecting the generated ID? Try something like this:
SELECT ID FROM FINAL TABLE
(INSERT INTO users(username) VALUES(?))
See "Retrieval of result sets from an SQL data change statement" in the IBM Db2 documentation.

Related

How to get the primary keys column of a table in SQLite

In my exercise sheet, my teacher use a python interface with SQLite. But I preferred to work with SQLite on Datagrip.
I'm asked to write a function which take as argument a table and returns the primary key column. I found that writing function in SQLite wasn't possible and that I needed some php interface or whatever.
Anyway as far as it's just training to get some SQL knowledge I tried to write a query for a table which returns a table containing the primary keys of a table.
Using the PRAGMA table_info (Evenements) query I get this table :
So I copied it in a Test table and wrote this query which works :
SELECT name from Test where pk;
But I can't replace Test by PRAGMA table_info (Evenements) or table_info (Evenements).
Do you know if I can directly use the table_info result without having to copy it in a new table?

The function that you should use is pragma_table_info():
SELECT *
FROM pragma_table_info('Evenements')
You will get info about all the columns of the table Evenements.
If you want info only for the primary key add a WHERE clause:
WHERE pk

SQLiteexception database disk image is malformed

I have a weird error with a SQLite Database: You can download it here
Everytime I try to insert something in the Table "CurrencyTransactions" it fails because a new column called 7 appeared for no reason.
I tried to drop the table but
I ran PRAGMA integrity_check but I've this error then
Then I tried to export a .sql file and to import it again in a fresh new database but
1) If I import the structure only, it works fine and I don't have the 7 column anymore
2) If I import the entries then, it fails with this error:
It means something like: "Error in process #74: not an error"
To finish, I also tried this solution but the new database created is empty.
What can I do? I really need to save the entries.

What I suggest is in DB Browser.
File/Export/Database to SQL file.
Select All (for all tables)
Other options up to you other than Export Everything
Save the file.
Close the database.
Open a new database e.g nadekobotfix.db. (could be same name but different location)
Note 1-6 takes a minute or so (just under 60k).
Do the hard work according to :-
You may need to remove/ignore the first and last lines (BEGIN TRANSACTION; and the subsequent COMMIT;)
You would probably not be able to run the generated SQL directly due to constraints (tried this an failed with constraints).
You need to copy sections from the file and run according to the hierarchy as imposed by the constraints (foreign keys). If you have CHECK constraints these may need to be considered. (no Triggers to worry about).
Running SELECT * FROM sqlite_master WHERE type = 'table' AND instr(sql,'CHECK'); returns nothing so there are no CHECK constraints.
Indexes could/should be left till last (as they are in the generated SQL).
A section would consist of a table's create statement along with the insert statements.
You may wish to create a spreadsheet of the tables(sections) marking them off when they have been done.
The following query could assist as those with NA could be done first
SELECT CASE WHEN instr(sql,'FOREIGN KEY') THEN 'FK' ELSE 'NA' END AS fkey, name,sql
FROM sqlite_master
WHERE type = 'table' AND name NOT LIKE 'sqlite%' ORDER BY instr(sql,'FOREIGN KEY')
you could export individual tables from DB Browser for SQlite marking them off when done.
You may wish to do an integrity_check at regular intervals.
If this works (you might have to make adjustments to the SQL) then you can rename the old db and then rename the new (or move the old and the copy the new if using the same database name).
Note you may still have to determine how the corruption occurred.
You may wish to backup the database regularly.
You may wish to have a look at How To Corrupt An SQLite Database File
You may wish to heed :-
With few exceptions, analysis of a corrupt database does not normally
help to determine what went wrong. A better approach to avoiding
"danger", we have found, is to read and understand
https://www.sqlite.org/howtocorrupt.html
* in database main *
Page 10628: btreeInitPage() returns error code 11
This indicates that the page header is so badly corrupted that SQLite
cannot interpret this page at all. One possible reason: page 10628
has been zeroed. Can you look at a hex dump of that page? (Remember
that SQLite numbers pages beginning with 1, so the start of the page
is pgsz*10627 where pgsz is the page size.)
-- D. Richard Hipp
“btreeInitPage() returns error code 11”
Sample adjustment required
The Reminders table has a column called When, this is an SQL keyword (inadvisable column name IMO) so the generated SQL for the INSERT doesn't wrap the column name so you will get an error.
i.e. :-
CREATE TABLE IF NOT EXISTS `Reminders` (
`Id` INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
`ChannelId` INTEGER NOT NULL,
`IsPrivate` INTEGER NOT NULL,
`Message` TEXT,
`ServerId` INTEGER NOT NULL,
`UserId` INTEGER NOT NULL,
`When` TEXT NOT NULL,
`DateAdded` TEXT
);
INSERT INTO `Reminders` (Id,ChannelId,IsPrivate,Message,ServerId,UserId,When,DateAdded) VALUES (1270,367886754973351936,1,'Birthday Day',318127386367623170,367886754973351936,'2018-05-03 22:07:48.1860996','2018-03-18 22:07:48.186101'),
(1271,248278722656993281,1,'to remind Chanmi to remind Jayos to DeagleMomoka',318127386367623170,248278722656993281,'2018-05-05 22:08:58.4915565','2018-03-18 22:08:58.4915582'),
(1376,170240129414201344,1,'timely',318127386367623170,170240129414201344,'2018-03-29 09:00:29.4476776','2018-03-28 09:00:29.447679'),
(1377,373301201158144000,1,'timely',318127386367623170,373301201158144000,'2018-03-29 09:50:14.1631563','2018-03-28 09:50:14.1631577'),
(1378,248278722656993281,1,'timely',318127386367623170,248278722656993281,'2018-03-29 11:24:27.0250275','2018-03-28 11:24:27.025029'),
(1379,421433212716318721,1,'to timely',318127386367623170,421433212716318721,'2018-03-29 19:21:17.7465563','2018-03-28 19:21:17.7465584'),
(1380,346513954966863872,1,'t',318127386367623170,346513954966863872,'2018-03-29 19:42:23.4758798','2018-03-28 19:42:23.4758816'),
(1381,272735316002209792,1,'t!daily',318127386367623170,272735316002209792,'2018-03-29 21:01:47.5616218','2018-03-28 21:01:47.5616236'),
(1382,298272937243312132,1,'timely',318127386367623170,298272937243312132,'2018-03-29 23:18:02.8826873','2018-03-28 23:18:02.8826891'),
(1383,332340162774302720,1,'t',318127386367623170,332340162774302720,'2018-03-30 01:55:21.4704139','2018-03-29 01:55:21.4704156'),
(1384,367165474246754314,1,'tatyahaksodoeo',318127386367623170,367165474246754314,'2018-03-30 03:46:18.8805182','2018-03-29 03:46:18.8805196'),
(1385,290086674761908225,1,'timely',318127386367623170,290086674761908225,'2018-03-30 07:02:33.4115303','2018-03-29 07:02:33.4115321'),
(1386,168064128500367360,1,'timely',318127386367623170,168064128500367360,'2018-03-30 07:19:09.1915867','2018-03-29 07:19:09.1915885');
would have to be changed to use (square brackets, single or double quotes or grave accents can be used to enclose/wrap/quote the offending keyword):-
.......INSERT INTO `Reminders` (Id,ChannelId,IsPrivate,Message,ServerId,UserId,[When],DateAdded) ......
Likewise table SelfAssignableRoles has the GROUP keyword as a column name.
Likewise table Permissionv2 and table StartupCommand have the INDEX keyword as a column name.
Potential Issue
As an exercise I've tried doing the above and have managed to get 67 out of the 71 tables (66 out of 70 of your tables as sqlite_sequence is automatically created).
However, there appears to be an issue, between the Clubs table and the DiscordUser table. I believe that there is a circular reference between them. Thus as WaifuInfo and WaifuUpdates are reliant upon the DiscordUser table and as WaifuItem is realiant upon WaifInfo. The tables mentioned here have not been successfully copied.
A word of warning. If you attempt to create Clubs and or DiscordUser using the existing constraints you may end up in a situation where one always has to exist.
e.g. if DiscordUser exists but Clubs doesn't then
DROP TABLE IF EXISTS `DiscordUser`;
results in :-
no such table: main.Clubs: DROP TABLE IF EXISTS `DiscordUser`;
If you then create Clubs and try the DROP with a very basic (no Constraints) using :-
CREATE TABLE IF NOT EXISTS `Clubs` (ID INTEGER PRIMARY KEY);
DROP TABLE IF EXISTS `DiscordUser`;
The result is good as per :-
Query executed successfully: DROP TABLE IF EXISTS `DiscordUser`; (took 1ms)
Now try to DROP Clubs using :-
--CREATE TABLE IF NOT EXISTS `Clubs` (ID INTEGER PRIMARY KEY);
--DROP TABLE IF EXISTS `DiscordUser`;
DROP TABLE IF EXISTS `Clubs`;
and you can't as DiscordUser doesn't exist as per :-
no such table: main.DiscordUser: DROP TABLE IF EXISTS `Clubs`;
I've tried closing the database in case it was a caching issue but the behaviour remains.
As such, I'd strongly suggest having a good look at the constraint usage and being sure of correcting the issues before trying to copy all of the tables (I guess that there is a chance that this could be part of the cause of the corruption, however why/how is way beyond me).
P.S. The method I used was (1-6):-
Then for 7 :-
Run the sqlite_master query, from above, select all cells and copy, then drop the results into a spreadsheet (you could drop the sql column as the create gets truncated unless you try to fiddle with the delimiters).
Open the exported file (I used NotePad++) in your Editor.
Open a new DB in DB Browser (will refer to it as DBB from now) for SQLite.
In DBB in EXEC SQL tab, input PRAGMA integrity_check, run to check.
Create new tab (for next SQL).
Switch to Spreadsheet and copy the first table name that isn't marked as done.
Switch to Editor do find on EXISTS copied_table_name
Select the section (i.e the CREATE statement along to and including the last row to be inserted, note can be a pain for the larger tables so might be easier to create separate export for those tables). Copy the selection to the clipboard.
Paste into the empty tab and run.
If OK then
in DBB click to create a new tab for the next
switch to spreadsheet and mark table as DONE
goto 5.
If not OK then
If you can fix the issue by altering the SQL fix the SQL (e.g. column name needs enclosing/wrapping/quoting) and then go to 9.
If the issue is due to Constraints then go to 5 but select the table causing the constraint.
OK the issue with the DiscordUser/Club tables is that a Clubs.Ownerid requires a DiscordUser. So clubs cannot be added without the relevant Discord users (id's 1,2,7,14 and 32). Some DiscordUsers are club members so they require a club to exist.
What I have done is to load the DiscordUsers rows for the Club owners changing their ClubId to null. Load the Clubs. Update the ClubId's of the DiscordUsers so they are members of the club that they were before (i.e. undo the null) and to load the rest of the nearly 600 Discordusers (excluding those already loaded).
Here's the SQL I used for that part (note except for the Discorduser, Clubs and the 3 waifu tables, all other tables have been successfully created and loaded).
INSERT INTO `DiscordUser` (Id,AvatarId,Discriminator,UserId,DateAdded,Username,ClubId,LastLevelUp,NotifyOnLevelUp,LastXpGain,TotalXp,IsClubAdmin,CurrencyAmount) VALUES
-- ClubId was 6 changed to null
(1,'6d5212a0f5e862d57c8ffc6f254a2e85','1458',299779864045682689,'2017-10-07 18:02:04.8287878','Anubis',NULL,'2018-03-27 02:22:26.362966',0,'2017-11-17 01:19:14.0313957',7056,1,280),
-- Owns a club but not in a club
(2,'3b37e0f635706f81fdde2b6de9889283','9810',181200115539640321,'2017-10-07 18:04:39.767728','AnnaHime',NULL,'2018-01-02 02:27:38.8011863',0,'2017-11-16 01:29:49.0371488',429,0,360),
-- ClubId null was 3
(7,'612c67b6eb57d8806dcc92ed45b3a6d0','0396',177502331582021639,'2017-10-07 18:11:09.7830603','Tsuchimursu',NULL,'2018-03-28 17:45:53.7399883',0,'2017-11-17 15:53:59.084885',18156,1,4725),
-- ClubId null was 4
(14,'b2dd362171277337294de325bf92ad6a','3267',215597863441268737,'2017-10-07 18:45:54.8092675','LaLa☆Star',NULL,'2018-01-14 20:52:15.7531274',0,'2017-11-08 19:00:22.7778305',2061,1,286),
-- ClubId null was 5
(32,'667f4d802b977c4d4be974e35ae63c55','2593',251689019929395200,'2017-10-08 00:58:16.6089546','username',NULL,'2018-03-28 07:27:34.9348084',0,'2017-11-17 20:02:14.0283998',4704,1,1188),
-- ClubId was 2 changed to NULL
(91,'0adb399c9f2cd94370038e2452ab8c8d','6790',346513954966863872,'2017-10-13 05:48:51.7788964','mayoi',NULL,'2018-03-24 02:50:06.8970518',0,'2017-11-17 20:01:29.0692552',7635,1,515)
;
INSERT INTO `Clubs` (Id,DateAdded,Discrim,ImageUrl,MinimumLevelReq,Name,OwnerId,Xp,Description) VALUES
(2,'2017-11-14 07:39:57.5091592',1,'https://lh3.googleusercontent.com/_7WKFouxTx1fdFpnmmuykDAd5SoiiJOPzHdRmXKOmRRZhV5Ba4V_kZct5ooVjQ9BuzU=w300',5,'We ⤠waifus',91,40137,'Love your waifus short & tall, big & small, cute as dolls, we love ''em all!'),
(3,'2017-12-11 07:00:59.3762914',1,'',30,'Den of Faes',7,11607,NULL),
(4,'2017-12-11 07:03:59.093402',1,'',5,'Skeleton Enthusiasts',14,657,NULL),
(5,'2017-12-11 07:05:56.9111719',1,'',5,'Saki''s Juice',32,2610,NULL),
(6,'2017-12-22 04:46:24.7271709',1,'',5,'nap pile',1,24870,'For the sleeping beauties and the wandering insomniacs who enjoy a good night sleep.')
;
UPDATE `DiscordUser` SET ClubId = 6 WHERE Id=1;
UPDATE `DiscordUser` SET ClubId = 3 WHERE Id=7;
UPDATE `DiscordUser` SET ClubId = 4 WHERE Id=14;
UPDATE `DiscordUser` SET ClubId = 5 WHERE Id=32;
UPDATE `DiscordUser` SET ClubId = 2 WHERE Id=91;
-- LOAD Remaining DiscordUser rows (note incomplete)
INSERT INTO `DiscordUser` (Id,AvatarId,Discriminator,UserId,DateAdded,Username,ClubId,LastLevelUp,NotifyOnLevelUp,LastXpGain,TotalXp,IsClubAdmin,CurrencyAmount) VALUES
--(1,'6d5212a0f5e862d57c8ffc6f254a2e85','1458',299779864045682689,'2017-10-07 18:02:04.8287878','Anubis',6,'2018-03-27 02:22:26.362966',0,'2017-11-17 01:19:14.0313957',7056,1,280),
--(2,'3b37e0f635706f81fdde2b6de9889283','9810',181200115539640321,'2017-10-07 18:04:39.767728','AnnaHime',NULL,'2018-01-02 02:27:38.8011863',0,'2017-11-16 01:29:49.0371488',429,0,360),
(3,'a3cd92d397ad357834d0e6c9f10bfc59','0429',145356302347010048,'2017-10-07 18:04:49.786657','Rebel Lucy',NULL,'2018-03-26 12:55:21.1149964',0,'2017-11-17 22:21:24.0263741',6876,0,3600),
(4,'7225dccaab1c93896657a61e18595378','5286',84689434536050688,'2017-10-07 18:05:44.765554','scarletflame234',NULL,'2018-03-28 22:56:28.7427437',0,'2017-11-17 23:21:41.4446535',13368,0,288),
(5,'c1316bc0673f4a2709b3ce550ed54395','0760',303279191116480514,'2017-10-07 18:06:39.7664015','zachary',NULL,'2018-03-02 03:48:43.4817755',0,'2017-11-17 18:44:14.1082867',210,0,50),
(6,'2ed95eae7c3088c46b23e71578dacc42','8801',161369834314137601,'2017-10-07 18:07:04.7672808','Kou',NULL,'2018-03-07 06:24:32.3405246',0,'2017-11-17 23:20:00.0648699',2640,0,55),
--(7,'612c67b6eb57d8806dcc92ed45b3a6d0','0396',177502331582021639,'2017-10-07 18:11:09.7830603','Tsuchimursu',3,'2018-03-28 17:45:53.7399883',0,'2017-11-17 15:53:59.084885',18156,1,4725),
(8,'5b1d239935ab4dd6d3eee98954601d52','9859',179093512610906113,'2017-10-07 18:13:54.7939334','TheCorty',NULL,'2017-11-12 12:07:36.4752178',0,'2017-11-12 23:47:26.4744132',2460,0,205), ...........
NOTE The SQL from -- LOAD Remaining DiscordUser rows, will not work as it's only intended to show how ID's 1,2 and 7 have been commented out, as should be rows 14, 32 and 91 as they have already been loaded, the other close to 600 rows should be included.
Note I've just also loaded the outstanding 3 waifu tables so all data can be retrieved (assuming that none has been lost due to the corruption). PRAGMA integrity_check; returns OK.

Adding Row in existing table (SQL Server 2005)

I want to add another row in my existing table and I'm a bit hesitant if I'm doing the right thing because it might skew the database. I have my script below and would like to hear your thoughts about it.
I want to add another row for 'Jane' in the table, which will be 'SKATING" in the ACT column.
Table: [Emp_table].[ACT].[LIST_EMP]
My script is:
INSERT INTO [Emp_table].[ACT].[LIST_EMP]
([ENTITY],[TYPE],[EMP_COD],[DATE],[LINE_NO],[ACT],[NAME])
VALUES
('REG','EMP','45233','2016-06-20 00:00:00:00','2','SKATING','JANE')
Will this do the trick?

Your statement looks ok. If the database has a problem with it (for example, due to a foreign key constraint violation), it will reject the statement.
If any of the fields in your table are numeric (and not varchar or char), just remove the quotes around the corresponding field. For example, if emp_cod and line_no are int, insert the following values instead:
('REG','EMP',45233,'2016-06-20 00:00:00:00',2,'SKATING','JANE')

Inserting records into a database has always been the most common reason why I've lost a lot of my hairs on my head!
SQL is great when it comes to SELECT or even UPDATEs but when it comes to INSERTs it's like someone from another planet came into the SQL standards commitee and managed to get their way of doing it implemented into the final SQL standard!
If your table does not have an automatic primary key that automatically gets generated on every insert, then you have to code it yourself to manage avoiding duplicates.
Start by writing a normal SELECT to see if the record(s) you're going to add don't already exist. But as Robert implied, your table may not have a primary key because it looks like a LOG table to me. So insert away!
If it does require to have a unique record everytime, then I strongly suggest you create a primary key for the table, either an auto generated one or a combination of your existing columns.
Assuming the first five combined columns make a unique key, this select will determine if your data you're inserting does not already exist...
SELECT COUNT(*) AS FoundRec FROM [Emp_table].[ACT].[LIST_EMP]
WHERE [ENTITY] = wsEntity AND [TYPE] = wsType AND [EMP_COD] = wsEmpCod AND [DATE] = wsDate AND [LINE_NO] = wsLineno
The wsXXX declarations, you will have to replace them with direct values or have them DECLAREd earlier in your script.
If you ran this alone and recieved a value of 1 or more, then the data exists already in your table, at least those 5 first columns. A true duplicate test will require you to test EVERY column in your table, but it should give you an idea.
In the INSERT, to do it all as one statement, you can do this ...
INSERT INTO [Emp_table].[ACT].[LIST_EMP]
([ENTITY],[TYPE],[EMP_COD],[DATE],[LINE_NO],[ACT],[NAME])
VALUES
('REG','EMP','45233','2016-06-20 00:00:00:00','2','SKATING','JANE')
WHERE (SELECT COUNT(*) AS FoundRec FROM [Emp_table].[ACT].[LIST_EMP]
WHERE [ENTITY] = wsEntity AND [TYPE] = wsType AND
[EMP_COD] = wsEmpCod AND [DATE] = wsDate AND
[LINE_NO] = wsLineno) = 0
Just replace the wsXXX variables with the values you want to insert.
I hope that made sense.

Oracle: selfcopying data from Oracle tables

Application has different versions. Each version has it's own set of values in each table. I need to provide functionality to copy data from one version to another. Problem :
By inserting data I am trying to insert Ids which has already been in use in this table. So, I need to change ids of components which I want to insert but I must save relationship between those components. How cat I do that?

Create a master table which has a surrogate key as your primary key. A numeric value of type NUMBER(9) works well. You can create a sequence and trigger to automatically insert this.
The rest of the table is the column of your current table plus a column to indicate which version the row is for.
For simplicity you may wish to create views on top of the table along the lines of
select * from master_table where version_id = ####;
To copy the data from one version to another this will work:
Insert into master_table seq_master_table.nextval, new version_id,.....
from master_table
where version_id = ####;

How do you copy Sql table from one database to another database with differ field names

I have a database name "EmpOld" with a table name "Employee" and a database name "EmpNew" with a table name "Employee".
The table structures are identical on both database tables except for the names in the table.
Here is a definition of the tables:
Database "EmpOld" table name "Employee" has following field names:
int e_id
char(20) e_fname
char(25) e_lname
Database "EmpNew" table "Employee" has following field names:
int id
char(20) fname
char(25) lname
Notice, the only difference in the tables is the "e_" prefix for field names are removed from the EmpNew Employee table.
How do I move data from EmpOld database to EmpNew database?
Is there a code that maps these field respectively.
Thanks community,
Nick

Well, you could just name them manually:
INSERT dbo.EmpNew(fname, lname) SELECT e_fname, e_lname FROM dbo.EmpOld;
If you want to do this without manually typing out the column names, there is magic in SSMS - just drag the Columns folder from each table into the appropriate spot in your query window (and then manually remove identity columns, timestamp, computed columns etc. if relevant).

There is no automatic way of mapping fields, unless with some code.
This can be done in two ways:
Using the SQL Import & Export Wizard
This is the most easy way to do this and here is an article that gives step by step to do this. The key is to change the mapping between the source and destination fields while importing the data.
Writing an SQL
This method requires both the databases to be accessible. Using a simple insert statement as follows this can be achieved
insert into EmpNew.dbo.Employee(id, fname, lname)
select
e_id, e_fname, e_lname
from
EmpOld.dbo.Employee
If they are on same sql server then the above will work good as is. If they are different sql server you may have to add a link server connection and prefix the table commands with that.

Is there a code that maps these field respectively.
No - you'll need to provide the mapping. If you're using an ETL tool like SSIS there may be a way to programatically map columns based on some criteria, but nothing built into SQL.

Maybe you can generate code with help from the tables sys.columns and other system tables so that you can make the copy-process run automatically.
I think you can't use:
insert into (...) (...)
because you have two databases. So just generate insert statements like:
insert into table (...) VALUES (...)
Please correct me if i misunderstood the question.

There are 2 ways you can do without the data loss.
1) you can use Insert statement
`
Insert into EmpNew (ID,fname,lname)
Select e_id, e_fname, e_lastname
from EmpOld
`
2) You can simple use Import-Export Wizard
Go to Start Menu > SQL Server 2008/2008R2/2012 > ImportandExport>
This will take you the wizard box
Select Source :- DataSource(ServerName) and Database where you are
extracting data from
Select Destination : DataSource(ServerName) and Database where you are extracting data to
Map the table
BE AWARE of PK/FK/Identity
you are good to go