In pl/sql, if you create a variable as varchar2(256) and then assign a 10 character string to the variable then the total memory used is 256 characters but if you declare it (4000 or more it will use only the 10 characters. Is that also true for varchar columns on a table? Or does a varchar column always allocate only what you have assigned? Thanks.
The varchar column is meant to be 'variable character' so it stores just one more character (the terminal) than the string you are storing. char, stores exactly the number of characters it is set to.
Related
I have a query that I need formatted in a particular way, but when I have an 8-character string with a 12-character column name, it pads the column to 12 characters even with Set Heading Off and Set Pagesize 0. Is there a way to display a column such that it will not include the length of the column name when calculating the width to use?
This is not the same as "SQLPlus varchar2 outputs whitespaces", which does not appear to be asking about the case when the column name is longer than the data name - just when the data appears to have an excessive length.
How can i create a database table column, which accepts an inter of 18 characters length and similarly how can i create a database column of string of length 12 characters. I am using the postgresql database.
Int's have a max length of 11 characters in the db.
I believe if you make the migration that of a bigint then you could set a limit in the model as kuwantum suggests.
https://gist.github.com/stream7/1069589/e03f2b99a89ffad49cb7c9959e640ea1ac9d9ff1
The environment is SQL Server 2012. I'm about to change a clr procedure returned result column from varchar to nvarchar, but I'm not sure if the characters which can be found in varchar code page will always convert to the same character in unicode and also the other way. The bad example would be if someone would get the results from procedure with column of nvarchar and put that in database with varchar column. The question is, will they convert correctly always?
VARCHAR is specific to your system codepage. NVARCHAR holds Unicode characters. Unicode is always going to be a superset of any legacy codepage. As such, you can expect your conversions from VARCHAR -> NVARCHAR to map properly. However, if your NVARCHAR string later contains Unicode characters that are not found in your legacy codepage, the characters will be lost when converting back to VARCHAR.
When possible, you should avoid this type of conversion. Update the table column to NVARCHAR.
I have a db column for upc codes setup as a 'numeric' data type in postgres.
I generated scaffolding to input values into this table, but rails is converting the input in FLOAT for some reason,
eg, a 13 digit number entry 1234567890000 is converted to 1234567890000.0
from the logs:
INSERT INTO "upc_codes" ("upccode") VALUES (1234567890000.0) RETURNING "id"
Where is the data type for the SQL statement being set, or not set as the case may be?
What data type are using for this column? Try changing the column type to an integer in a migration:
change_column :upc_codes, :upc_code, :integer
max integer value for an mysql integer should be 2147483647 .
i will suppose this could cause an errors somewhere .
try to change the coulm into a bigint .
aniway ,from my experience is better to handle bignum using string in rails (in this manner you could saftly change db). you could always use to_i later in your code .
sorry for my english.
When you set the column type to NUMERIC are you specifying the precision/scale like this: NUMERIC(13,0)? (13 is precision, 0 is scale)
I submitted this again as an answer because I guess I commented when I should have answered.
How do I set the datatype for a ROWID in an input or output parameter?
ROWID is a peudocolumn in SQL statements. It is a calculated fixed length character column with a size of 18.
More information is available in the help file.