I have a table with a column configured to hold nvarchar data type.
I am trying to add a row using
INSERT INTO TABLE_NAME VALUES (value1, value2...)
Sql-server gets stuck on a 180 character string that I am trying to assign to the nvarchar data type column returning:
Error: The identifier that starts with [part of string] is too long.
Maximum length is 128.
I don't understand why this is happening since nvarchar(max) should hold 2GByte of storage as I read here: What is the maximum characters for the NVARCHAR(MAX)?
Any ideas of what I've got wrong here?
UPDATE:
The table was created with this:
CREATE TABLE MED_DATA (
MED_DATA_ID INT
,ORDER_ID INT
,GUID NVARCHAR
,INPUT_TXT NVARCHAR
,STATUS_CDE CHAR
,CRTE_DTM DATETIME
,MOD_AT_DTM DATETIME
,CHG_IN_REC_IND CHAR
,PRIMARY KEY (MED_DATA_ID)
)
And my actual INSERT statement is as follows:
INSERT INTO MED_DATA
VALUES (
5
,12
,"8fd9924"
,"{'firstName':'Foo','lastName':'Bar','guid':'8fd9924','weightChanged':false,'gender':'Male','heightFeet':9,'heightInches':9,'weightPounds':999}"
,"PENDING"
,"2017-09-02 00:00:00.000"
,"2017-09-02 00:00:00.000"
,NULL
)
By default, double quotes in T-SQL do not delimit a string. They delimit an identifier. So you cannot use double quotes here. You could change the default but shouldn't.
If this is being directly written in a query window, use single quotes for strings and then double up quotes within the string to escape them:
INSERT INTO MED_DATA VALUES (5, 12, '8fd9924', '{''firstName'':''Foo'',''lastName'':''Bar'',''guid'':''8fd9924'',''weightChanged'':false,''gender'':''Male'',''heightFeet'':9,''heightInches'':9,''weightPounds'':999}', 'PENDING', '2017-09-02T00:00:00.000', '2017-09-02T00:00:00.000', NULL)
But if, instead, you're passing this string across from another program, it's time to learn how to use parameterized queries. That'll also allow you to pass the dates across as dates and not rely on string parsing to reconstruct them correctly.
Also, as noted, you need to fix your table definitions because they've currently nvarchar which means the same as nvarchar(1).
Are you aware of what an Identifier is? Here is a hint - it is a NAME. SQL Server is not complaining about your data, it is complaining about a field or table name. SOmehow your SQL must be totally borked so that part of the text is parsed as name of a field or table. And yes, those are limited to 128 characters.
This is clear in the error message:
Error: The identifier
clearly states it is an identifier issue.
Related
I have seen prefix N in some insert T-SQL queries. Many people have used N before inserting the value in a table.
I searched, but I was not able to understand what is the purpose of including the N before inserting any strings into the table.
INSERT INTO Personnel.Employees
VALUES(N'29730', N'Philippe', N'Horsford', 20.05, 1),
What purpose does this 'N' prefix serve, and when should it be used?
It's declaring the string as nvarchar data type, rather than varchar
You may have seen Transact-SQL code that passes strings around using
an N prefix. This denotes that the subsequent string is in Unicode
(the N actually stands for National language character set). Which
means that you are passing an NCHAR, NVARCHAR or NTEXT value, as
opposed to CHAR, VARCHAR or TEXT.
To quote from Microsoft:
Prefix Unicode character string constants with the letter N. Without
the N prefix, the string is converted to the default code page of the
database. This default code page may not recognize certain characters.
If you want to know the difference between these two data types, see this SO post:
What is the difference between varchar and nvarchar?
Let me tell you an annoying thing that happened with the N' prefix - I wasn't able to fix it for two days.
My database collation is SQL_Latin1_General_CP1_CI_AS.
It has a table with a column called MyCol1. It is an Nvarchar
This query fails to match Exact Value That Exists.
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = 'ESKİ'
// 0 result
using prefix N'' fixes it
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = N'ESKİ'
// 1 result - found!!!!
Why? Because latin1_general doesn't have big dotted İ that's why it fails I suppose.
1. Performance:
Assume your where clause is like this:
WHERE NAME='JON'
If the NAME column is of any type other than nvarchar or nchar, then you should not specify the N prefix. However, if the NAME column is of type nvarchar or nchar, then if you do not specify the N prefix, then 'JON' is treated as non-unicode. This means the data type of NAME column and string 'JON' are different and so SQL Server implicitly converts one operand’s type to the other. If the SQL Server converts the literal’s type
to the column’s type then there is no issue, but if it does the other way then performance will get hurt because the column's index (if available) wont be used.
2. Character set:
If the column is of type nvarchar or nchar, then always use the prefix N while specifying the character string in the WHERE criteria/UPDATE/INSERT clause. If you do not do this and one of the characters in your string is unicode (like international characters - example - ā) then it will fail or suffer data corruption.
Assuming the value is nvarchar type for that only we are using N''
I have seen prefix N in some insert T-SQL queries. Many people have used N before inserting the value in a table.
I searched, but I was not able to understand what is the purpose of including the N before inserting any strings into the table.
INSERT INTO Personnel.Employees
VALUES(N'29730', N'Philippe', N'Horsford', 20.05, 1),
What purpose does this 'N' prefix serve, and when should it be used?
It's declaring the string as nvarchar data type, rather than varchar
You may have seen Transact-SQL code that passes strings around using
an N prefix. This denotes that the subsequent string is in Unicode
(the N actually stands for National language character set). Which
means that you are passing an NCHAR, NVARCHAR or NTEXT value, as
opposed to CHAR, VARCHAR or TEXT.
To quote from Microsoft:
Prefix Unicode character string constants with the letter N. Without
the N prefix, the string is converted to the default code page of the
database. This default code page may not recognize certain characters.
If you want to know the difference between these two data types, see this SO post:
What is the difference between varchar and nvarchar?
Let me tell you an annoying thing that happened with the N' prefix - I wasn't able to fix it for two days.
My database collation is SQL_Latin1_General_CP1_CI_AS.
It has a table with a column called MyCol1. It is an Nvarchar
This query fails to match Exact Value That Exists.
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = 'ESKİ'
// 0 result
using prefix N'' fixes it
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = N'ESKİ'
// 1 result - found!!!!
Why? Because latin1_general doesn't have big dotted İ that's why it fails I suppose.
1. Performance:
Assume your where clause is like this:
WHERE NAME='JON'
If the NAME column is of any type other than nvarchar or nchar, then you should not specify the N prefix. However, if the NAME column is of type nvarchar or nchar, then if you do not specify the N prefix, then 'JON' is treated as non-unicode. This means the data type of NAME column and string 'JON' are different and so SQL Server implicitly converts one operand’s type to the other. If the SQL Server converts the literal’s type
to the column’s type then there is no issue, but if it does the other way then performance will get hurt because the column's index (if available) wont be used.
2. Character set:
If the column is of type nvarchar or nchar, then always use the prefix N while specifying the character string in the WHERE criteria/UPDATE/INSERT clause. If you do not do this and one of the characters in your string is unicode (like international characters - example - ā) then it will fail or suffer data corruption.
Assuming the value is nvarchar type for that only we are using N''
I have table with an integer column.
CREATE TABLE [dbo].[tble1](
[id] [int] NOT NULL,
[test] [nchar](10) NULL
)
When I try to insert some values and pass an empty string to the id column like below, it gets inserted and the value of the id column is 0 by default.
INSERT INTO [dbo].[tble1]
([id],[test])
VALUES
('','a')
I couldn't find any satisfying reasoning behind it. Could some one please share your thoughts on this?
What is happening is that '' is being converted to an integer. The rules are that a string can be converted, based on the digit characters in the string.
If a string is empty, it gets converted to 0.
So, the conversion is happening at the very "top" level. The types don't match so SQL Server attempts an implicit conversion.
Unfortunately, the documentation is not really clear on the topic:
Character expressions that are being converted to an exact numeric
data type must consist of digits, a decimal point, and an optional
plus (+) or minus (-). Leading blanks are ignored. Comma separators,
such as the thousands separator in 123,456.00, are not allowed in the
string.
To be honest, I would interpret the "must consist of digits" as saying that there must be at least one digit (although technically in English "zero" is treated as a plural, I don't necessarily think of plurals as including zero elements). However, the empty string has been used -- pretty much for forever -- as a valid value for any type across a broad range of databases.
It will try to Convert ' ' to Integer and it got succeeded.
SELECT CONVERT(INT, '')
Output
0
You are getting defaulted value to 0, as you have NOT null, defined for the column,
if you keep ID as null, then it will put NULL,
Also, if you want to populate the value automatically then you set the identity for the column
I have seen prefix N in some insert T-SQL queries. Many people have used N before inserting the value in a table.
I searched, but I was not able to understand what is the purpose of including the N before inserting any strings into the table.
INSERT INTO Personnel.Employees
VALUES(N'29730', N'Philippe', N'Horsford', 20.05, 1),
What purpose does this 'N' prefix serve, and when should it be used?
It's declaring the string as nvarchar data type, rather than varchar
You may have seen Transact-SQL code that passes strings around using
an N prefix. This denotes that the subsequent string is in Unicode
(the N actually stands for National language character set). Which
means that you are passing an NCHAR, NVARCHAR or NTEXT value, as
opposed to CHAR, VARCHAR or TEXT.
To quote from Microsoft:
Prefix Unicode character string constants with the letter N. Without
the N prefix, the string is converted to the default code page of the
database. This default code page may not recognize certain characters.
If you want to know the difference between these two data types, see this SO post:
What is the difference between varchar and nvarchar?
Let me tell you an annoying thing that happened with the N' prefix - I wasn't able to fix it for two days.
My database collation is SQL_Latin1_General_CP1_CI_AS.
It has a table with a column called MyCol1. It is an Nvarchar
This query fails to match Exact Value That Exists.
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = 'ESKİ'
// 0 result
using prefix N'' fixes it
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = N'ESKİ'
// 1 result - found!!!!
Why? Because latin1_general doesn't have big dotted İ that's why it fails I suppose.
1. Performance:
Assume your where clause is like this:
WHERE NAME='JON'
If the NAME column is of any type other than nvarchar or nchar, then you should not specify the N prefix. However, if the NAME column is of type nvarchar or nchar, then if you do not specify the N prefix, then 'JON' is treated as non-unicode. This means the data type of NAME column and string 'JON' are different and so SQL Server implicitly converts one operand’s type to the other. If the SQL Server converts the literal’s type
to the column’s type then there is no issue, but if it does the other way then performance will get hurt because the column's index (if available) wont be used.
2. Character set:
If the column is of type nvarchar or nchar, then always use the prefix N while specifying the character string in the WHERE criteria/UPDATE/INSERT clause. If you do not do this and one of the characters in your string is unicode (like international characters - example - ā) then it will fail or suffer data corruption.
Assuming the value is nvarchar type for that only we are using N''
I have seen prefix N in some insert T-SQL queries. Many people have used N before inserting the value in a table.
I searched, but I was not able to understand what is the purpose of including the N before inserting any strings into the table.
INSERT INTO Personnel.Employees
VALUES(N'29730', N'Philippe', N'Horsford', 20.05, 1),
What purpose does this 'N' prefix serve, and when should it be used?
It's declaring the string as nvarchar data type, rather than varchar
You may have seen Transact-SQL code that passes strings around using
an N prefix. This denotes that the subsequent string is in Unicode
(the N actually stands for National language character set). Which
means that you are passing an NCHAR, NVARCHAR or NTEXT value, as
opposed to CHAR, VARCHAR or TEXT.
To quote from Microsoft:
Prefix Unicode character string constants with the letter N. Without
the N prefix, the string is converted to the default code page of the
database. This default code page may not recognize certain characters.
If you want to know the difference between these two data types, see this SO post:
What is the difference between varchar and nvarchar?
Let me tell you an annoying thing that happened with the N' prefix - I wasn't able to fix it for two days.
My database collation is SQL_Latin1_General_CP1_CI_AS.
It has a table with a column called MyCol1. It is an Nvarchar
This query fails to match Exact Value That Exists.
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = 'ESKİ'
// 0 result
using prefix N'' fixes it
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = N'ESKİ'
// 1 result - found!!!!
Why? Because latin1_general doesn't have big dotted İ that's why it fails I suppose.
1. Performance:
Assume your where clause is like this:
WHERE NAME='JON'
If the NAME column is of any type other than nvarchar or nchar, then you should not specify the N prefix. However, if the NAME column is of type nvarchar or nchar, then if you do not specify the N prefix, then 'JON' is treated as non-unicode. This means the data type of NAME column and string 'JON' are different and so SQL Server implicitly converts one operand’s type to the other. If the SQL Server converts the literal’s type
to the column’s type then there is no issue, but if it does the other way then performance will get hurt because the column's index (if available) wont be used.
2. Character set:
If the column is of type nvarchar or nchar, then always use the prefix N while specifying the character string in the WHERE criteria/UPDATE/INSERT clause. If you do not do this and one of the characters in your string is unicode (like international characters - example - ā) then it will fail or suffer data corruption.
Assuming the value is nvarchar type for that only we are using N''