 |
» |
|
|
|
ALLBASE/SQL converts the type of a value in the following
situations: Including values of different types
in the same expression. Moving data from a host variable to a column or
a column to a host variable of a different type.
The valid type combinations are shown in Table 7-1 “ALLBASE/SQL Data Types” Table 7-3 Valid Type Combinations | Source Data Type | Target Data Type |
|---|
| CHAR or VARCHAR | CHAR or VARCHAR | | | DATE, TIME DATETIME,
or INTERVAL when CHAR value involved in date/time math or inserted into
or compared to a date/time column | | CHAR or VARCHAR | BINARY or VARBINARY
(from host variable/constant into a binary column only) | | BINARY or VARBINARY | BINARY or VARBINARY | | BINARY or VARBINARY | CHAR or VARCHAR (from column
into host variable, or comparing a binary column with a char column
or value) | | DECIMAL, FLOAT, REAL, INTEGER, SMALLINT | Any numeric type | | DATE, TIME, DATETIME, INTERVAL | CHAR or VARCHAR (except in LIKE
predicate) |
In some cases, such as the following, data conversion can
lead to overflow or truncation: Overflow can occur during these conversions: - FLOAT
to DECIMAL, INTEGER or SMALLINT - FLOAT
to REAL - REAL
to DECIMAL, INTEGER, or SMALLINT - DECIMAL
to DECIMAL, INTEGER, or SMALLINT - INTEGER
to DECIMAL or SMALLINT - SMALLINT
to DECIMAL
Overflow of the integer part and truncation of the
fractional part of a number can occur during a FLOAT-to-DECIMAL
conversion, because ALLBASE/SQL aligns the decimal points. Truncation of the fractional part of a value occurs
during these conversions: - DECIMAL
to SMALLINT or INTEGER - DECIMAL
to DECIMAL when the target scale is smaller than
the source scale - FLOAT
to INTEGER, SMALLINT, DECIMAL, or REAL - REAL
to INTEGER, SMALLINT, or DECIMAL
Truncation can occur during these conversions if
the target is too small: - DATE, TIME, DATETIME or
INTERVAL
to VARCHAR or CHAR - CHAR
to VARCHAR, BINARY or VARBINARY - VARCHAR
to CHAR, BINARY or VARBINARY - VARBINARY
to BINARY, CHAR or VARCHAR - BINARY
to VARBINARY, CHAR, or VARCHAR
When you use numeric data of different types in an expression
or comparison operation, the data type of the lesser type is converted
to that of the greater type, and the result is expressed in the
greater type. Numeric types have the following precedence: Comparison operations or expressions involving different numeric
data types result in conversion from one data type to another as
explained in Table 7-4 “Conversions from Combining Different Numeric
Data Types” Table 7-4 Conversions from Combining Different Numeric
Data Types | Operations containing: | Result: |
|---|
| DECIMAL and INTEGER types only | All participating integers are
converted to DECIMAL quantities having a precision of 10 and a scale
of 0. | | DECIMAL and SMALLINT types only | All participating SMALLINT values
are converted to DECIMAL quantities having a precision of 5 and
a scale of 0. | | One item of type FLOAT | All participating integer and
decimal operands are converted to FLOAT quantities and precision
can be lost. | | One item of type REAL | All arithmetic involving REAL operands results
in a type of FLOAT. All participating integer and decimal operands
are converted to FLOAT quantities and precision can be lost. |
|
