I have a sql table which data type is int and it doesn’t accept null value.
So what I want to do is add “null” using derived column.
What I did is used drived transformation and add a new column and use expression (DT_WSTR,10) “null”
And then used data conversion and changed the data type into DT_14 but the data conversion fails upon execution.
Is there any other way to do this?
You can't do what you're trying to do. An INTEGER NOT NULL column will throw an error if you try to insert a text value into it, as you've seen.
There are really only two options.
Insert a zero for any NULL values that come through.
Insert a dummy value that's out of the range of values for the column, such as 999999 or the minimum or maximum values for an integer data type.
Or, of course, as Gordon suggested in the comments, drop the NOT NULL constraint on the column and insert the NULL values.
Related
I am getting an insert error:
Cannot insert the value NULL into column 'id', table 'db.dbo.table';
column does not allow nulls. INSERT fails
.
I have checked the data and the column I am inserting into 'id' does not have any nulls.
Any suggestions?
The error
column does not allow nulls
is happening because you are trying to insert data which has NULL for the column id, for at least one record which you are trying to insert. It has nothing to do with the state of the column before you attempted the insert. Check the source of your insertion data and remove/replace the NULL values, or alter the id column to accept NULL.
When looking at your SQL table design, scroll through "Column Properties" to "Identity Specification". In that drop-down, change "(Is Identity)" to Yes. This setting tells the table to auto-increment the ID field.
Null is not a particular value, but rather, an indication that you don't know the value for this field. It means, "VALUE UNKNOWN". If the field is not NULLable (i.e., if "UNKNOWN" is not permissible), then the INSERT will not be allowed. This is particularly true for an ID column, which might be INDEXed — perhaps even the PRIMARY KEY of the table. Some databases do not allow NULL in INDEXes (particularly primary indexes) at all.
I've created a table schema and specified that for some attributes, values cannot be null. For one column of this table, values are to be imported from a column of some another table but the problem i am facing is that when i use insert statement to copy values from that column of another table to the column of this newly created table, the attributes of this new column start screaming because they kind of have a constraint on them that while insertion their values cannot be NULL!
How do i cope with this?
One solution is that for other attributes, just for time being, i can state that null values can be accommodated so that i can successfully import values from column of other table and then later on put condition on the remaining attributes that values are not be NULL. But how do i do do this?
You need to convert NULL to some DEFAULT values while importing.
I am not sure which DB engine you are using, in mysql:
Use something like IFNULL(column_name, "").
Reference
You may simply be looking for the default clause. When you define a column, you can specify;
intcol int not null default 0
If the column is not specified for an insert, then it will default to 0. In some databases, if a NULL value is supplied, it will also get the default value.
I am working in SQL Server 2008. I have a table with many columns that will not have values (at least, for the given situation). So, they will have a NULL value when I query each of them. I would like to instead make these NULL values be empty strings (i.e., ''). What is the best way to achieve this? My current idea is to set a DEFAULT value of '' on each them at the time that the table is created. However, since there are so many of them, this will be very tedious.
You have 2 options:
As you said, give it a default value of empty string for columns you don't want to be null when you create table/add new columns.
When you select nullable columns from the table you can use IsNull(ColumnName,'') which means if ColumnName is null it'll return empty string ('').
Create a table with the same structure as your current table, with a different name, and the default value as ''.
Insert into that table from your original table.
Delete the original table.
Change the name of the new table to the original table name.
I just started working with SQL Server and I have some troubles with adding values to a table with a column of type uniqueidentifier.
The table consists of:
ID (uniqueidentifier), CODE (nchar(5)), COUNTRY_CODE(nchar(2)), NAME(nchar30)
I tried adding values from Excel and CSV files, basically they look like this:
DEBE,DE,Berlin
I could not load it, always have some errors with this ID field.
When i try to add values manually like:
INSERT INTO [Portfolio].[dbo].[Regions](CODE, COUNTRY_CODE, NAME)
VALUES ('DEBE', 'DE', 'Berlin');
It says:
Cannot insert the value NULL into column 'ID', table
'Portfolio.dbo.Regions'; column does not allow nulls. INSERT fails.
Of course when I add an id column and a number, I get info that int is incompatible with uniqueidentifier.
I even tried creating a temp table (with id as an INT instead of uniqueidentifier) and copying values from it into this (without ID column, its supposed to generate automatically)
Only thing I can think of is that ID column is not creating values for it automatically and I don't know how to solve this. Can anyone help?
Uniqueidentifier is a special type you can use to generate GUID. Is 16 byte long and is not incremented automatically as the Identity columns. You need to use Convert or Cast clause in order to get the correct uniqueidentifier from a varchar, if it exceeds the 16bytes it will be truncated.
Use NewID() to generate a new uniqueidentifier.
Maybe this link can help you
As mentioned above, use NewID() to create an identifier.
When you are in the design mode for the table, NewID() can be placed in the 'Default Value or Binding' slot. This means that for any new record that you insert into the table (such as CODE, COUNTRY_CODE, NAME), a Unique Identifier will be created.
What I think you are looking for is an Identity field. The UniqueIdentifier field is used for storing GUID's.
Change the field type to int and then change it's Identity Specification to 'Yes".
The other solution would be to pass the ID field your own GUID from code.
Too late to answer, but it may help someone, go to you sql table design mode,
select your required table's attribute, here in detail tab (down to table) you'll see a property
RowGuid --> Yes (make sure to turn it to yes).
Cheers :)
I want to add or update columns using alter table if i am adding a new column i want show error. I am using the code below
alter table Personal_Details alter columns DOB datetime
if i uncheck the NULL to not NULL then it will shows column does not allow nulls; update fails;
i want to insert the fields in between columns not at end.
Plese fix my bug,
Thanks in advance.
The position of the column in the table declaration has nothing to do with its being NULL or NOT NULL.
If you are adding a column (of any type) which you want to be NOT NULL, i.e. you want to prohibit NULL values in that column, and the table already contains some rows, you must also provide some default value. For example:
ALTER TABLE Personal_Details
ADD COLUMN DOB datetime NOT NULL DEFAULT (GETDATE())
Otherwise the engine will attempt to add that column with NULLs as its values, which will violate the NOT NULL property, and the change, therefore, will be reverted.
Basically, the same applies when you want to set an existing column's NOT NULL property on while the column already contains NULLs. But in this case you must explicitly eliminate the NULLs before the change by either replacing them with values or removing the respective rows.
Source:
ALTER TABLE (Transact-SQL). (The particular section related to your problem is just above this code snippet.)
1)For ur adding column with not null problem
Use
ALTER TABLE Personal_Details ADD COLUMN DOB datetime NULL
Update the DOB column with the required dates and make sure there is no null in the column
then alter the column using
ALTER TABLE Personal_Details ALTER COLUMN DOB datetime not NULL
2)For your column going to the end problem...
you should not be worried...the order in which the columns are arranged doesnt matter...unless u are using a pathetic way of accessing data by column order..in which case again..u should stop accessing it by column order...
If the column order really matters you can change it using design option in the sql management table(rightclick on table >design and drag the column to its required place.)