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.
Related
The primary key of my table is an Identity column of an ID. I want to be able to insert a new row and have it know what the last ID in the table currently is and add one to it. I know I can use Scope Identity to get the last inserted column from my code, but I am worried about people manually adding entries in the database, because they do this quite often. Is there a way I can look at the last ID in the table and not just the last ID my code inserted?
With a SQL Identity column, you don't need to do anything special. This is the default behavior. SQL Server will handle making sure you don't have collisions regardless of where the inserts come from.
The ##Identity will pull the latest identity, and scope_identity will grab the identity from the current scope.
A scope is a module: a stored procedure, trigger, function, or batch. Therefore, if two statements are in the same stored procedure, function, or batch, they are in the same scope.
If you don't want to allow manual entries to the primary column, then you can add Identity constraint to it along with primary key constraint.
Example, while creating a table,
CREATE Table t_Temp(RowID Int Primary Key Identity(1,1), Name Varchar(50))
INSERT Into t_Temp values ('UserName')
INSERT Into t_Temp values ('UserName1')
SELECT * from t_Temp
You can query the table and get the next available code in one SQL query:
SELECT COALESCE(MAX(CAST("RowID" AS INT)),0) +1 as 'NextRowID' from <tableName>
The "0" here is a default, meaning if there are no rows found, the first code returned would be (0+1) =1
Generally I have 999 instead of the 0 as I like my RowID/primary key etc. to start at 1000.
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 = ####;
I applied 12Lac Insert command in Single table ,
but after some time query terminated , How can I find Last
Inserted Record
a)Table don't have created Date column
b)Can not apply order by clause because primary key values are manually generated
c)Last() is not buit in fumction in mssql.
Or any way to find last executed query
There will be some way but not able to figure out
Table contain only primary key constrain no other constrain
As per comment request here a quick and dirty manual solution, assuming you've got the list of INSERT statements (or the according data) in the same sequence as the issued INSERTs. For this example I assume 1 million records.
INSERT ... VALUES (1, ...)
...
INSERT ... VALUES (250000, ...)
...
INSERT ... VALUES (500000, ...)
...
INSERT ... VALUES (750000, ...)
...
INSERT ... VALUES (1000000, ...)
You just have to find the last PK, that has been inserted. Luckily in this case there is one. So you start doing a manual binary search in the table issuing
SELECT pk FROM myTable WHERE pk = 500000
If you get a row back, you know it got so far. Continue checking with pk = 750000. Then again, if it is there with pk = 875000. If 750000 is not there, then the INSERTs must have stopped earlier. Then check for pk = 675000. This process stops in this case after 20 steps.
It's just plain manual divide and conquer.
There is a way.
Unfortunately you have to do this in advance so it helps you.
So if you have, by any chance the PRIMARY KEYS you inserted, still at hand go ahead and delete all rows that have those keys:
DELETE FROM tableName WHERE ID IN (id1, id2, ...., idn)
Then you enable Change Data Capture for your database (have the db already selected):
EXEC sys.sp_cdc_enable_db;
Now you also need to enable Change Data Capture for that table, in an example that I've tried I could just run:
EXEC sys.sp_cdc_enable_table #source_schema = N'dbo', #source_name = N'tableName', #role_name = null
Now you are almost setup! You need to look into your system services and verify that SQL Server Agent is running for your DBMS, if it does not capturing will not happen.
Now when you insert something into your table you can select data changes from a new table called [cdc].[dbo_tableName_CT]:
SELECT [__$start_lsn]
,[__$end_lsn]
,[__$seqval]
,[__$operation]
,[__$update_mask]
,[ID]
,[Value]
FROM [cdc].[dbo_tableName_CT]
GO
An example output of this looks like this:
you can order by __$seqval that should give you the order in which the rows were inserted.
NOTE: this feature seems not to be present in SQL Server Express
I'm trying to find a query for sql that will just insert values but not do it should the value exist. Now ive seen alot of examples but they all rely on primary keys or table to table moves. I just want to add a new row in the table and assuming that one of the collumns doesnt have the same value add it. I know the following wont work but its as close to I think it would be and might just clear it up if my writting is not enough.
INSERT INTO table (txtLastName,txtEmail,txtZip)
Values ('Tester','test#test.com','12345')
WHERE txtLastName <> 'Tester'
or WHERE txtEmail <> 'test#test.com'
or WHERE txtZip <> '12345'
Using MS SQL Server.
You should create a Unique Constraint composed by the three fields (txtLastName, txtEmail, txtZip).
The links directs you to SQL Server docs, but the concept of unique constraint is RDBMS universal.
Just beware that when you create a Unique Constraint, your duplicate insert will not just fail silently: it will throw an error saying the insert tried to violate the unique constraint. And, of course, it should do that! Make sure your code handles that exception.
Try this:
INSERT INTO table (txtLastName,txtEmail,txtZip)
SELECT 'Tester','test#test.com','12345'
WHERE NOT EXISTS (SELECT *
FROM table
WHERE txtLastName = 'Tester'
AND txtEmail = 'test#test.com'
AND txtZip = '12345'
)
I have this table which doesn't have a primary key.
I'm going to insert some records in a new table to analyze them and I'm thinking in creating a new primary key with the values from all the available columns.
If this were a programming language like Java I would:
int hash = column1 * 31 + column2 * 31 + column3*31
Or something like that. But this is SQL.
How can I create a primary key from the values of the available columns? It won't work for me to simply mark all the columns as PK, for what I need to do is to compare them with data from other DB table.
My table has 3 numbers and a date.
EDIT What my problem is
I think a bit more of background is needed. I'm sorry for not providing it before.
I have a database ( dm ) that is being updated everyday from another db ( original source ) . It has records form the past two years.
Last month ( july ) the update process got broken and for a month there was no data being updated into the dm.
I manually create a table with the same structure in my Oracle XE, and I copy the records from the original source into my db ( myxe ) I copied only records from July to create a report needed by the end of the month.
Finally on aug 8 the update process got fixed and the records which have been waiting to be migrated by this automatic process got copied into the database ( from originalsource to dm ).
This process does clean up from the original source the data once it is copied ( into dm ).
Everything look fine, but we have just realize that an amount of the records got lost ( about 25% of july )
So, what I want to do is to use my backup ( myxe ) and insert into the database ( dm ) all those records missing.
The problem here are:
They don't have a well defined PK.
They are in separate databases.
So I thought that If I could create a unique pk from both tables which gave the same number I could tell which were missing and insert them.
EDIT 2
So I did the following in my local environment:
select a.* from the_table#PRODUCTION a , the_table b where
a.idle = b.idle and
a.activity = b.activity and
a.finishdate = b.finishdate
Which returns all the rows that are present in both databases ( the .. union? ) I've got 2,000 records.
What I'm going to do next, is delete them all from the target db and then just insert them all s from my db into the target table
I hope I don't get in something worst : - S : -S
The danger of creating a hash value by combining the 3 numbers and the date is that it might not be unique and hence cannot be used safely as a primary key.
Instead I'd recommend using an autoincrementing ID for your primary key.
Just create a surrogate key:
ALTER TABLE mytable ADD pk_col INT
UPDATE mytable
SET pk_col = rownum
ALTER TABLE mytable MODIFY pk_col INT NOT NULL
ALTER TABLE mytable ADD CONSTRAINT pk_mytable_pk_col PRIMARY KEY (pk_col)
or this:
ALTER TABLE mytable ADD pk_col RAW(16)
UPDATE mytable
SET pk_col = SYS_GUID()
ALTER TABLE mytable MODIFY pk_col RAW(16) NOT NULL
ALTER TABLE mytable ADD CONSTRAINT pk_mytable_pk_col PRIMARY KEY (pk_col)
The latter uses GUID's which are unique across databases, but consume more spaces and are much slower to generate (your INSERT's will be slow)
Update:
If you need to create same PRIMARY KEYs on two tables with identical data, use this:
MERGE
INTO mytable v
USING (
SELECT rowid AS rid, rownum AS rn
FROM mytable
ORDER BY
co1l, col2, col3
)
ON (v.rowid = rid)
WHEN MATCHED THEN
UPDATE
SET pk_col = rn
Note that tables should be identical up to a single row (i. e. have same number of rows with same data in them).
Update 2:
For your very problem, you don't need a PK at all.
If you just want to select the records missing in dm, use this one (on dm side)
SELECT *
FROM mytable#myxe
MINUS
SELECT *
FROM mytable
This will return all records that exist in mytable#myxe but not in mytable#dm
Note that it will shrink all duplicates if any.
Assuming that you have ensured uniqueness...you can do almost the same thing in SQL. The only problem will be the conversion of the date to a numeric value so that you can hash it.
Select Table2.SomeFields
FROM Table1 LEFT OUTER JOIN Table2 ON
(Table1.col1 * 31) + (Table1.col2 * 31) + (Table1.col3 * 31) +
((DatePart(year,Table1.date) + DatePart(month,Table1.date) + DatePart(day,Table1.date) )* 31) = Table2.hashedPk
The above query would work for SQL Server, the only difference for Oracle would be in terms of how you handle the date conversion. Moreover, there are other functions for converting dates in SQL Server as well, so this is by no means the only solution.
And, you can combine this with Quassnoi's SET statement to populate the new field as well. Just use the left side of the Join condition logic for the value.
If you're loading your new table with values from the old table, and you then need to join the two tables, you can only "properly" do this if you can uniquely identify each row in the original table. Quassnoi's solution will allow you to do this, IF you can first alter the old table by adding a new column.
If you cannot alter the original table, generating some form of hash code based on the columns of the old table would work -- but, again, only if the hash codes uniquely identify each row. (Oracle has checksum functions, right? If so, use them.)
If hash code uniqueness cannot be guaranteed, you may have to settle for a primary key composed of as many columns are required to ensure uniqueness (e.g. the natural key). If there is no natural key, well, I heard once that Oracle provides a rownum for each row of data, could you use that?