You must supply names (identifiers) to satisfy the syntax of SQL
statements that require user-supplied names. In statement syntax
diagrams, user-supplied names are shown in lowercase type.
User-supplied names must:
o Be no more than 31 octets (8-bit characters).
o Conform to one of the following rules:
- If the identifier character set is MCS, the name must
contain only alphanumeric characters and begin with an
uppercase or lowercase letter. Alphanumeric characters are
uppercase or lowercase letters (A, a), including letters
with diacritical marks (À), digits, dollar signs ($), and
underscores (_).
Uppercase and lowercase letters are treated equally.
Although dollar signs are valid characters in names, to
avoid conflicts it is recommended that you do not use them.
You cannot begin a user-supplied name with a numeric
character.
- If the identifier character set is other than DEC_MCS, it
can contain only a valid sequence of characters as defined
by the standard for that character set.
- The name can be a delimited identifier. A delimited
identifier is a user-supplied name enclosed in double
quotation marks ("). It can start with and contain
alphanumeric characters, special characters, control
characters, and spaces. The quotation mark (") character
can be included in a delimited identifier by typing two
quotation marks together (see the following example).
Trailing spaces are not significant. See the Oracle Rdb
SQL Reference Manual for a list of special characters.
The alphabetic characters can be uppercase or lowercase.
The following example shows many variations of delimited
identifiers:
SQL> SET QUOTING RULES 'SQL99
SQL> CREATE TABLE "This is a Test"
cont> ("""" CHAR(5),
cont> "_NAME" CHAR(20),
cont> " City" CHAR(20),
cont> "1st_date" DATE,
cont> "A ""B and C""" CHAR(10),
cont> "$_Amount" INT,
cont> """Test" CHAR(5)
cont> );
SQL> SHOW TABLE (COLUMN) "This is a Test";
Information for table This is a Test
Columns for table This is a Test:
Column Name Data Type Domain
----------- --------- ------
" CHAR(5)
_NAME CHAR(20)
City CHAR(20)
1st_date DATE VMS
A "B and C" CHAR(10)
$_Amount INTEGER
"Test CHAR(5)
If you use a delimited identifier, SQL maintains the
case of the identifier. That is, if you enclose the
identifier Employee_ID in quotation marks ("Employee_ID"),
SQL preserves the uppercase and lowercase letters. The
delimited identifiers "Employee_ID", "EMPLOYEE_ID", and
"employee_id" are distinct from each other.
You must enable ANSI/ISO SQL quoting when using delimited
identifiers.
If you want to use a keyword as a user-supplied name, you must
set the quoting rules or dialect to SQL99 and use the delimited
identifier.
SQL uses the identifier character set as the character set for
database object names. However, because SQL interprets the names
of some database objects as file names or path names, you must
use only ASCII alphanumeric characters for the names of the
following database objects:
o Database file name
o Database path name
o Snapshot files
o Storage areas
o Journal files
o Alias names
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