What is the maximum length of a table name in Oracle?

Question

What are the maximum length of a table name and column name in Oracle?

Answer 1

In Oracle 12.2 and above the maximum object name length is 128 bytes.

In Oracle 12.1 and below the maximum object name length is 30 bytes.

Answer 2

Teach a man to fish

Notice the data-type and size

>describe all_tab_columns

VIEW all_tab_columns

Name                                      Null?    Type                        
 ----------------------------------------- -------- ----------------------------
 OWNER                                     NOT NULL VARCHAR2(30)                
 TABLE_NAME                                NOT NULL VARCHAR2(30)                
 COLUMN_NAME                               NOT NULL VARCHAR2(30)                
 DATA_TYPE                                          VARCHAR2(106)               
 DATA_TYPE_MOD                                      VARCHAR2(3)                 
 DATA_TYPE_OWNER                                    VARCHAR2(30)                
 DATA_LENGTH                               NOT NULL NUMBER                      
 DATA_PRECISION                                     NUMBER                      
 DATA_SCALE                                         NUMBER                      
 NULLABLE                                           VARCHAR2(1)                 
 COLUMN_ID                                          NUMBER                      
 DEFAULT_LENGTH                                     NUMBER                      
 DATA_DEFAULT                                       LONG                        
 NUM_DISTINCT                                       NUMBER                      
 LOW_VALUE                                          RAW(32)                     
 HIGH_VALUE                                         RAW(32)                     
 DENSITY                                            NUMBER                      
 NUM_NULLS                                          NUMBER                      
 NUM_BUCKETS                                        NUMBER                      
 LAST_ANALYZED                                      DATE                        
 SAMPLE_SIZE                                        NUMBER                      
 CHARACTER_SET_NAME                                 VARCHAR2(44)                
 CHAR_COL_DECL_LENGTH                               NUMBER                      
 GLOBAL_STATS                                       VARCHAR2(3)                 
 USER_STATS                                         VARCHAR2(3)                 
 AVG_COL_LEN                                        NUMBER                      
 CHAR_LENGTH                                        NUMBER                      
 CHAR_USED                                          VARCHAR2(1)                 
 V80_FMT_IMAGE                                      VARCHAR2(3)                 
 DATA_UPGRADED                                      VARCHAR2(3)                 
 HISTOGRAM                                          VARCHAR2(15)                

Answer 3

DESCRIBE all_tab_columns

will show a TABLE_NAME VARCHAR2(30)

Note VARCHAR2(30) means a 30 byte limitation, not a 30 character limitation, and therefore may be different if your database is configured/setup to use a multibyte character set.

Mike

Answer 4

Right, but as long as you use ASCII characters even a multibyte character set would still give a limitation of exactly 30 characters... so unless you want to put hearts and smiling cats in you're DB names your fine...

Answer 5

Updated: as stated above, in Oracle 12.2 and later, the maximum object name length is now 128 bytes.

The rest of this post applied to Oracle 12.1 and below: the limit was then 30 char (bytes, really).

But do not take my word for it; try this for yourself (on Oracle 12.1 or below):

SQL> create table I23456789012345678901234567890 (my_id number);

Table created.



SQL> create table I234567890123456789012345678901(my_id number);


ERROR at line 1:

ORA-00972: identifier is too long

Answer 6

The schema object naming rules may also be of some use:

http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/sql_elements008.htm#sthref723

Answer 7

On Oracle 12.2, you can use built-in constant, ORA_MAX_NAME_LEN, set to 128 bytes (as per 12.2) Prior to Oracle 12.1 max size was 30 bytes.

Answer 8

In the 10g database I'm dealing with, I know table names are maxed at 30 characters. Couldn't tell you what the column name length is (but I know it's > 30).

Answer 9

The maximum name size is 30 characters because of the data dictionary which allows the storage only for 30 bytes

Answer 10

Oracle database object names maximum length is 30 bytes.

Object Name Rules: http://docs.oracle.com/database/121/SQLRF/sql_elements008.htm

Answer 11

I'm working on Oracle 12c 12.1. However, doesn't seem like it allows more than 30 characters for column/table names.

Read through an oracle page which mentions 30 bytes. https://docs.oracle.com/database/121/SQLRF/sql_elements008.htm#SQLRF00223

In 12c although the all_tab_columns do say VARCHAR2(128) for Table_Name, it does not allow more than 30 bytes name.

Found another article about 12c R2, which seems to be allowing this up to 128 characters. https://community.oracle.com/ideas/3338

Answer 12

The maximum length of the table and column name is 128 bytes or 128 characters. This limit is for using sybase database users. I verified this answer thoroughly, so that I have posted this answer confidently.