NonStop SQL/MP Reference Manual

NonStop SQL/MP Reference Manual—142115
L-7
Limits
A comment line in a catalog table cannot exceed 132 characters. The maximum
number of lines allowed is 10,000.
•
Constraint definition
The search condition that defines a constraint must be less than 3,000 bytes.
The code generated for the combined search conditions of all constraints associated
with a table must be less than 31,000 bytes.
•
Cursors
One object file can have up to a billion cursors. Assuming 300 bytes for each SQL
statement object, 4 megabytes would hold 12,000 cursors. If the cursor definitions
are complex or have large names, or there are many input or output variables, the
limit becomes smaller.
•
Data length
Fixed-length character data has a minimum length of one character. Varying-length
character data has a minimum length of 0 characters, but the length field is two
bytes. The maximum length of a character column depends on the file organization
of the table that contains the column, on whether the character set associated with
the column is a single or double-byte character set, and on whether the data type
specifies a fixed of varying length.
A column that allows null values requires two extra bytes.
For clustering keys and system-defined primary keys, SQL requires 8 bytes for a
system-defined key called SYSKEY.
A string literal can be as long as a character column. See Data Types
on page D-1
for more information.
A numeric literal cannot exceed 18 digits.
•
Default value for a character column
The maximum length for the default value is 8 characters.
•
First key length
A specification for the first key for partitions cannot exceed the length of the user-
defined primary key or clustering key for tables or the length of the index key for
indexes. (See the Index length item later in this subsection.)
•
FROM clause tables
Data Type Key-Sequenced Relative or Entry-Sequenced
Single-byte unvarying 4061 4072
Single-byte VARYING 4059 4070
Double-byte unvarying 2030 2036
Double-byte
VA RY IN G
2029 2035