Openedge Data Management: SQL Reference - Product ...

Data types
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CHARACTER [ ( length ) ]
CHARACTER (alias CHAR) corresponds to a null-terminated character string with the length
specified. Values are padded with blanks to the specified length. The default length is 1.
The maximum length is 2,000 characters.
The OpenEdge SQL representation is a variable-length string. The host language
representation is equivalent to a C language character string.
{ CHARACTER VARYING | CHAR VARYING | VARCHAR | LVARCHAR } [ ( length ) ]
CHARACTER VARYING, CHAR VARYING, and VARCHAR corresponds to a variable-length
character string with the maximum length specified. The default length is 1 character. The
maximum length is 31,995 characters. LVARCHAR has a maximum length of 1,073,741,823.
A CLOB is an object of data type LVARCHAR.
Notes • For data types CHARACTER( length ) and VARCHAR( length ) the value of length
specifies the number of characters.
Example
• The maximum length can be as large as 31,995. The sum of all the column lengths
of a table row must not exceed 31,960.
• Due to index size limitations, only the narrower VARCHAR columns can be indexed.
Maximum length for VARCHAR
The maximum length of the VARCHAR data type depends on:
• The number of columns in a table — More columns in a table further limits the length
of VARCHAR data.
• When a table was created — Tables created earlier can support longer VARCHAR data than
tables created later.
National Language Support (NLS)
The VARCHAR data type has NLS. The choice of character set affects the available character
count or maximum length of the data column. The limits established above assume a
single–byte character set. Using a multiple–byte character set lowers the maximum character
count proportionally. For example, if all the characters in a character set take 3 bytes per
character, the practical maximum is 10,660 (31,982 divided by 3). If, however, you are using a
variable–width character set, you will be able to hold between 10,660 and 31,982 characters,
depending on the actual mix of characters you use.
Concatenation operator
Use the concatenation operator (||) to join two text strings together.
The following example provides an example of a concatenation operator used in a query:
SELECT firstname || ' ' || lastname from Employee;