Informix® supports several
data types to store numbers:
Table 1. Informix numeric
data types
| Informix data type |
Description |
| SMALLINT |
16 bit signed integer |
| INT / INTEGER |
32 bit signed integer |
| BIGINT |
64 bit signed integer |
| INT8 |
64 bit signed integer (replaced
by BIGINT) |
| DEC / DECIMAL |
Equivalent to DECIMAL(16) |
| DEC(p) / DECIMAL(p) |
Floating-point decimal number |
| DEC(p,s) / DECIMAL(p,s) |
Fixed-point decimal number |
| MONEY |
Equivalent to DECIMAL(16,2) |
| MONEY(p) |
Equivalent to DECIMAL(p,2) |
| MONEY(p,s) |
Equivalent to DECIMAL(p,s) |
| REAL / SMALLFLOAT |
32-bit floating point decimal
(C float) |
| DOUBLE PRECISION / FLOAT[(n)] |
64-bit floating point decimal
(C double) |
Genero db supports the following:
Table 2. Genero db numeric data types
| Genero db data type |
Pseudotype |
Description |
| SMALLINT |
TINYINT / BIT |
16-bit signed integer |
| INT / INTEGER |
|
32-bit signed integer |
| BIGINT |
|
64-bit signed integer |
| INT8 |
|
64-bit signed integer |
| DECIMAL(p,s) |
|
Fixed-point decimal number (p<=15
with GDS 3.61) |
| NUMERIC(p,s) |
|
Fixed-point decimal number (p<=15
with GDS 3.61) |
| MONEY |
|
Number with precision nearly 19
and scale 4 |
| DOUBLE / DOUBLE PRECISION / REAL |
SMALLFLOAT / FLOAT(n) |
Approximate 64-bit floating point
real number (C double) |
Note:
- With Genero db 3.61, the maximum number of digits is 15,
while Genero db 3.80 supports up to 36digits.
- The only difference between DECIMAL and NUMERIC is that NUMERIC
guarantees the specified precision, whereas DECIMAL guarantees at
least the specified precision.
- A pseudotype is accepted anywhere a regular type name is, but
is silently converted into another type which is supported by Genero
db.
Solution
We recommend that you use the following
conversion rules:
Table 3. Numeric data type conversion rules
(Informix - Genero db)
| Informix data
type |
Genero db data type |
| SMALLINT |
SMALLINT |
| INTEGER |
INTEGER |
| BIGINT |
BIGINT |
| INT8 |
BIGINT |
| DECIMAL (equivalent to DECIMAL(16)) |
N/A until Genero db 3.90 |
| DECIMAL(p) |
N/A until Genero db 3.90 |
| DECIMAL(p,s) |
DECIMAL(p,s) with p <=15
if Genero db 3.61 |
| MONEY(p,s) |
DECIMAL(p,s) with p <=15
if Genero db 3.61 |
| REAL / SMALLFLOAT |
REAL (64b!) |
| DOUBLE PRECISION / FLOAT(n) |
FLOAT |
Note: Genero db does not have a 32-bit floating
point type, Informix SMALLFLOAT
has to be converted to REAL, which is a 64-bit floating point type
in Genero db. Later, when extracting the schema of the database, the
original type name used to create the table in Genero db can be used
to distinguish 32-bit from 64-bit types in the .sch schema file.