Setting Field Properties

Name

The Name is a descriptive identifier for a field that can be up to 63 characters 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.

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:

The Type dropdown list defines the type of the field data.

The following table shows all the built-in general-purpose data types for PostgreSQL 8.3. Most of the alternative names listed in the "Aliases" column are the names used internally by PostgreSQL for historical reasons.

Note: Some built-in general-purpose data types are not applicable for PostgreSQL 8.2 or earlier versions.

Name Aliases Description
bigint int8 signed eight-byte integer
bigserial serial8 autoincrementing eight-byte integer
bit [ (n) ]   fixed-length bit string
bit varying [ (n) ] varbit variable-length bit string
boolean bool logical Boolean (true/false)
box   rectangular box in the plane
bytea   binary data ("byte array")
character varying [ (n) ] varchar [ (n) ] variable-length character string
character [ (n) ] char [ (n) ] fixed-length character string
cidr   IPv4 or IPv6 network address
circle   circle in the plane
date   calendar date (year, month, day)
double precision float8 double precision floating-point number
inet   IPv4 or IPv6 host address
integer int, int4 signed four-byte integer
interval [ (p) ]   time span
line   infinite line in the plane
lseg   line segment in the plane
macaddr   MAC address
money   currency amount
numeric [ (p, s) ] decimal [ (p, s) ] exact numeric of selectable precision
path   geometric path in the plane
point   geometric point in the plane
polygon   closed geometric path in the plane
real float4 single precision floating-point number
smallint int2 signed two-byte integer
serial serial4 autoincrementing four-byte integer
text   variable-length character string
time [ (p) ] [ without time zone ]   time of day
time [ (p) ] with time zone timetz time of day, including time zone
timestamp [ (p) ] [ without time zone ]   date and time
timestamp [ (p) ] with time zone timestamptz date and time, including time zone
tsquery   text search query
tsvector   text search document
txid_snapshot   user-level transaction ID snapshot
uuid   universally unique identifier
xml   XML data

Length
Define the length of the field.

Decimals
Define the number of digits after the decimal point (the scale) for Floating Point data type.

Dimension
Define column as variable-length multidimensional arrays.

Note: Be careful when shortening the field length as losing data might be caused.

Allow Null

Allow the NULL values for the field.

Note: To set NULL as default value, see Setting Other Field Properties.

Key

A Primary Key is a single field or combination of fields that uniquely defines a record. None of the fields that are part of the primary key can contain a null value.