I have a Oracle procedure, its return query
SELECT CODE "Կադաստրային ծածկագիր", ENTAKAYANI "Ենթակայան"
FROM ELECTRIC_ENTAKAYAN_500
WHERE SDO_RELATE(GEOM,SDO_GEOM.SDO_BUFFER(
MDSYS.SDO_GEOMETRY(2001, 2400000,
MDSYS.SDO_POINT_TYPE(8451136.4,4451591.2,NULL),
NULL, NULL), 2, 0.005)
,'mask=ANYINTERACT')='TRUE'
AND rownum <= 10;
and problem this length("Կադաստրային ծածկագիր") = 20, Oracle max size length filed 30 symbol, but my string Armenian languages its > 30 symbol.
How to find an another solution?
If you are using Oracle 12cR2 you could use identifiers that are up to 128 bytes.
Database Object Naming Rules:
If COMPATIBLE is set to a value of 12.2 or higher, then names must be from 1 to 128 bytes long with these exceptions:
Names of databases are limited to 8 bytes.
Names of disk groups, pluggable databases (PDBs), rollback segments, tablespaces, and tablespace sets are limited to 30 bytes.
If an identifier includes multiple parts separated by periods, then each attribute can be up to 128 bytes long. Each period separator, as well as any surrounding double quotation marks, counts as one byte. For example, suppose you identify a column like this:
"schema"."table"."column"
The schema name can be 128 bytes, the table name can be 128 bytes, and the column name can be 128 bytes. Each of the quotation marks and periods is a single-byte character, so the total length of the identifier in this example can be up to 392 bytes.
Please keep in mind that byte != character.
SELECT /*csv*/ 1 AS "Կադաստրային ծածկագիր" FROM dual;
/*
"Կադաստրային ծածկագիր"
1
*/
And counting characters/bytes:
SELECT
length('ադաստրային ծածկագիր 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890') AS char#
,lengthb('ադաստրային ծածկագիր 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890') AS bytes#
FROM dual;
/*
CHAR# BYTES#
---------- ----------
120 138
*/
Related
I am doing a large string lookup on a small table.
When I do the following query in MsAccess:
SELECT isBit
FROM [SqlServerTableName]
WHERE mycolumnName = "[String Greater Than 128 characters]"
I get the message:
The identifier that starts with [String Greater Than 128 characters] is too long.
Maximum length is 128.
Followed by:
Unclosed quotation mark after the character string [String Greater Than 128 characters]
And:
Incorrect Syntax Near [String Greater Than 128 characters]
Now, is there a way around this? This table is very small and will stay very small(<1000 records) so I am not worried about string comparisons.
This is because you are using double quotes (") instead of single quotes (').
SQL Server is treating this as an identifier, and not as a string literal value.
You should change the query to be the following:
SELECT isBit
FROM [SqlServerTableName]
WHERE mycolumnName = '[String Greater Than 128 characters]'
I have some large varchar values in Postgres that I want to SELECT and move somewhere else. The place they are going to uses VARCHAR(4095) so I only need at most 4095 bytes (I think that's bytes) and some of these varchars are quite big, so a performance optimization would be to SELECT a truncated version of them.
How can I do that?
Something like:
SELECT TRUNCATED(my_val, 4095) ...
I don't think it's a character length though, it needs to be a byte length?
The n in varchar(n) is the number of characters, not bytes. The manual:
SQL defines two primary character types: character varying(n) and
character(n), where n is a positive integer. Both of these types can
store strings up to n characters (not bytes) in length.
Bold emphasis mine.
The simplest way to "truncate" a string would be with left():
SELECT left(my_val, 4095)
Or just cast:
SELECT my_val::varchar(4095)
The manual once more:
If one explicitly casts a value to character varying(n) or
character(n), then an over-length value will be truncated to n
characters without raising an error. (This too is required by the SQL standard.)
I am using MySQL data base with Rails. I have created a field of type string. Are there any limits to its length? What about type text?
Also as text is variable sized, I believe there would be extra costs associated with using text objects. How important can they get, if at all?
CHAR
A fixed-length string that is always right-padded with spaces to the specified length when stored The range of Length is 1 to 255 characters. Trailing spaces are removed when the value is retrieved. CHAR values are sorted and compared in case-insensitive fashion according to the default character set unless the BINARY keyword is given.
VARCHAR
A variable-length string. Note: Trailing spaces are removed when the value is stored (this differs from the ANSI SQL specification)
The range of Length is 1 to 255 characters. VARCHAR values are sorted and compared in case-insensitive fashion unless the BINARY keyword is given
TINYBLOB, TINYTEXT
A TINYBLOB or TINYTEXT column with a maximum length of 255 (28 - 1) characters
BLOB, TEXT
A BLOB or TEXT column with a maximum length of 65,535 (216 - 1) characters , bytes = 64 KiB
MEDIUMBLOB, MEDIUMTEXT
A MEDIUMBLOB or MEDIUMTEXT column with a maximum length of 16,777,215 (224 - 1)characters , bytes = 16 MiB
LONGBLOB, LONGTEXT
A LONGBLOB or LONGTEXT column with a maximum length of 4,294,967,295 (232 - 1) characters , bytes = 4 GiB
See MySQL Data Types Quick Reference Table for more info.
also you can see MYSQL - String Type Overview
String, in general, should be used for short text. For example, it is a VARCHAR(255) under MySQL.
Text uses the larger text from the database, like, in MySQL, the type TEXT.
For information on how this works and the internals in MySQL and limits and such, see the other answer by Pekka.
If you are requesting, say, a paragraph, I would use text. If you are requesting a username or email, use string.
See the mySQL manual on String Types.
Varchar (String):
Values in VARCHAR columns are variable-length strings. The length can be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to 65,535 in 5.0.3 and later versions. The effective maximum length of a VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used.
Text: See storage requirements
If you want a fixed size text field, use CHAR which can be 255 characters in length maximum. VARCHAR and TEXT both have variable length.
I am loading and inserting data into an Oracle database. When I encounter special characters that look like Chinese characters, I am getting an error like row rejected because maximum size of column was exceeded. I am not getting this error for rows which have English characters which appear to be of same length for same column. I am using SUBSTR and TRIM function but it is not working. How can I determine whether the length of a string which is in Chinese exceeds column size?
if your columns are defined as VARCHAR2(XX) [for example VARCHAR2(20)], you will receive an error if you try to insert a string that is more than XX bytes long.
The function SUBSTR calculates length in number of characters, not bytes. To select a substring in bytes, use the function SUBSTRB.
SQL> select substr('ЙЖ', 1, 2) from dual;
SUBSTR('ЙЖ',1,2)
------------------
ЙЖ
SQL> select substrb('ЙЖ', 1, 2) from dual;
SUBSTRB('ЙЖ',1,2)
-------------------
Й
Edit: As suggested by Adam, you can use character arithmetics if you define your columns and variables as VARCHAR2 (XX CHAR). In that case your columns will be able to store XX characters, in all character sets (up to a maximum of 4000 bytes if you store it in a table).
In Oracle, what is the difference between :
CREATE TABLE CLIENT
(
NAME VARCHAR2(11 BYTE),
ID_CLIENT NUMBER
)
and
CREATE TABLE CLIENT
(
NAME VARCHAR2(11 CHAR), -- or even VARCHAR2(11)
ID_CLIENT NUMBER
)
Let us assume the database character set is UTF-8, which is the recommended setting in recent versions of Oracle. In this case, some characters take more than 1 byte to store in the database.
If you define the field as VARCHAR2(11 BYTE), Oracle can use up to 11 bytes for storage, but you may not actually be able to store 11 characters in the field, because some of them take more than one byte to store, e.g. non-English characters.
By defining the field as VARCHAR2(11 CHAR) you tell Oracle it can use enough space to store 11 characters, no matter how many bytes it takes to store each one. A single character may require up to 4 bytes.
One has exactly space for 11 bytes, the other for exactly 11 characters. Some charsets such as Unicode variants may use more than one byte per char, therefore the 11 byte field might have space for less than 11 chars depending on the encoding.
See also http://www.joelonsoftware.com/articles/Unicode.html
Depending on the system configuration, size of CHAR mesured in BYTES can vary. In your examples:
Limits field to 11 BYTE
Limits field to 11 CHARacters
Conclusion: 1 CHAR is not equal to 1 BYTE.
I am not sure since I am not an Oracle user, but I assume that the difference lies when you use multi-byte character sets such as Unicode (UTF-16/32). In this case, 11 Bytes could account for less than 11 characters.
Also those field types might be treated differently in regard to accented characters or case, for example 'binaryField(ete) = "été"' will not match while 'charField(ete) = "été"' might (again not sure about Oracle).
In simple words when you write NAME VARCHAR2(11 BYTE) then only 11 Byte can be accommodated in that variable.
No matter which characters set you are using, for example, if you are using Unicode (UTF-16) then only half of the size of Name can be accommodated in NAME.
On the other hand, if you write NAME VARCHAR2(11 CHAR) then NAME can accommodate 11 CHAR regardless of their character encoding.
BYTE is the default if you do not specify BYTE or CHAR
So if you write NAME VARCHAR2(4000 BYTE) and use Unicode(UTF-16) character encoding then only 2000 characters can be accommodated in NAME
That means the size limit on the variable is applied in BYTES and it depends on the character encoding that how many characters can be accommodated in that vraible.