Data and Field Types

Visual Studio .NET 2003

All Visual FoxPro data has a type — a description of the permissible values and range and size of those values. Once you specify the type of data you are using, Visual FoxPro can efficiently store and manipulate the data.

Variables and arrays hold a subset of the available Visual FoxPro data types. Additional data types are available only for fields in a table. To add a field of a specific type to a table programmatically, specify the field type with a letter abbreviation. For more information, see the description for FieldType in CREATE TABLE - SQL.

You specify the type of data to be stored in each field of a table when you create the table. The type of data in a variable or array element is determined by the value you store in the variable or array element. The following table lists the data types in Visual FoxPro.

Visual FoxPro Data Types

Data type Description Size Range
Character Any text 1 byte per character to 254 Any characters
Currency Monetary amounts 8 bytes - 922337203685477.5807 to 922337203685477.5807
Date Chronological data consisting of month, year, and day 8 bytes When using strict date formats, {^0001-01-01}, January 1st, 1 A.D to {^9999-12-31}, December 31st, 9999 A.D.
DateTime Chronological data consisting of month, year, day, and time 8 bytes When using strict date formats, {^0001-01-01}, January 1st, 1 A.D to {^9999-12-31}, December 31st, 9999 A.D., plus 00:00:00 a.m. to 11:59:59 p.m.
Logical Boolean value of true or false 1 byte True (.T.) or False (.F.)
Numeric Integers or fractions 8 bytes in memory;
1 to 20 bytes in table
- .9999999999E+19 to .9999999999E+20
Variant A variant can contain any of the Visual FoxPro data types and the null value. Once a value is stored to a variant, the variant assumes the data type of the data it contains.

Variants are designated with an e prefix in language syntax.

See data types above. See data types above.

In addition, Visual FoxPro provides data types that apply only to fields in tables.

Visual FoxPro Field Types

Field type Description Size Range
Double A double-precision floating-point number 8 bytes +/-4.94065645841247E-324 to +/-8.9884656743115E307
Float Same as Numeric 8 bytes in memory;
1 to 20 bytes in table
- .9999999999E+19 to .9999999999E+20
General Reference to an OLE object 4 bytes in table Limited by available memory
Integer Integer values 4 bytes -2147483647 to 2147483647
Memo Reference to a block of data 4 bytes in table Limited by available memory
Character (Binary) Any character data you want to maintain without change across code pages 1 byte per character to 254 Any characters
Memo (Binary) Any memo field data you want to maintain without change across code pages 4 bytes in table Limited by available memory
Tip   You can use the TYPE( ) function to determine the type of data stored in a variable, array element, or field.

Each data type has its own characteristics, including storage size:

Data Type Storage Differences

To see a list of the functions you can use with each data type, see Language Categories.

See Also

ALTER TABLE - SQL Command | Character Data Type | CREATE TABLE - SQL Command | Currency Data Type | Date Data Type | DateTime Data Type | Double Field Type | Float Field Type | General Field Type | Logical Data Type | Memo Field Type | Numeric Data Type | Overview of the Language

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