Field Name
The Field Name is a descriptive identifier for a field that can be up to 30 bytes by default (letters or numbers) including spaces. The names should be descriptive enough that anyone can easily identify them when viewing or editing records. For example, LastName, FirstName, StreetAddress, or HomePhone.
Use the Name edit box to set the field name. Note that the name of the field must be unique among all the field names in the table.
Data Type
After you name a field, you choose a data type for the data to be contained in the field. When you choose a field's data type, you are deciding:
- What kind of values to allow in the field. You cannot store text in field with the Numeric data type.
- How much storage space Oracle is to set aside for the data in that field.
- What types of operations can be performed on the values in that field.
The Type dropdown list defines the type of the field data.
The following table shows all the built-in general-purpose data types.
Name | Description |
CHAR | fixed-length character strings |
NCHAR | fixed-length Unicode character data |
VARCHAR2 | variable-length character strings |
VARCHAR | variable-length character strings |
NVARCHAR2 | variable-length Unicode character data |
CLOB | database character set data |
NCLOB | Unicode national character set data |
LONG | variable-length character data containing up to 2 gigabytes of information |
NUMBER | fixed and floating-point numbers |
DATE | point-in-time values (dates and times) |
INTERVAL DAY TO SECOND | period of time in terms of days, hours, minutes, and seconds |
INTERVAL YEAR TO MONTH | stores a period of time using the YEAR and MONTH datetime fields |
TIMESTAMP | point-in-time values (dates and times) (includes fractional seconds) |
TIMESTAMP WITH TIME ZONE | TIMESTAMP with explicit time zone information |
BLOB | unstructured binary data in the database |
BFILE | unstructured binary data in operating-system files outside the database |
RAW | can be indexed and is used for data that is not to be interpreted by Oracle Database |
LONG RAW | cannot be indexed and is used for data that is not to be interpreted by Oracle Database |
ROWID | the address (rowid) of every row in the database |
CHARACTER | =CHAR 1 |
CHARACTER VARYING | =VARCHAR2 1 |
CHAR VARYING | =VARCHAR2 1 |
NATIONAL CHARACTER | =NCHAR 1 |
NATIONAL CHAR | =NCHAR 1 |
NATIONAL CHARACTER VARYING | =NVARCHAR2 1 |
NATIONAL CHAR VARYING | =NVARCHAR2 1 |
NCHAR VARYING | =NVARCHAR2 1 |
NUMERIC | =NUMBER 1 |
DECIMAL | =NUMBER 1 |
INTEGER | =NUMBER(38) 1 |
INT | =NUMBER(38) 1 |
SMALLINT | =NUMBER(38) 1 |
FLOAT | =FLOAT(126) 1 |
DOUBLE PRECISION | =FLOAT(126) 1 |
REAL | =FLOAT(63) 1 |
- Note:
- These are ANSI datatypes and datatypes from the IBM products SQL/DS and DB2. Oracle recognizes these datatypes and converts them to the equivalent Oracle datatype. Click here for detailed description on these datetypes.