How deeply does PostgreSQL Mistakes and How to Avoid Them cover Decimal?

Defines NUMERIC and DECIMAL equivalence, explains monetary trade-offs, and warns against cross-database type-name assumptions.

Decimal

As explained in PostgreSQL Mistakes and How to Avoid Them

NUMERIC is an exact SQL numeric data type for storing values with specified precision and scale.

Decimal, also called NUMERIC in PostgreSQL, stores exact numeric values with specified precision and scale. NUMERIC and DECIMAL are equivalent names in PostgreSQL. section 3.6

Use NUMERIC for monetary amounts instead of MONEY or floating-point types. MONEY does not record its currency and accepts malformed input, while real and double precision can introduce rounding errors. Store the currency in a separate adjacent column. section 3.6 section 3.9

Avoiding numeric type mismatches

During a migration, do not map another database's NUMBER type by name alone. Oracle NUMBER can represent integers and floating-point values, whereas PostgreSQL distinguishes numeric, integer, and floating-point types. Check each definition and use PostgreSQL conversion functions or migration tools to preserve precision and calculations. section 10.5

How PostgreSQL Mistakes and How to Avoid Them covers it

Cover of PostgreSQL Mistakes and How to Avoid Them

liveBook manning.com

Read PostgreSQL Mistakes and How to Avoid Them on liveBook Get the book at manning.com

Also explained in

liveBook manning.com

Build Financial Software with Generative AI (From Scratch)Decimal is Python's arbitrary-precision decimal arithmetic type for representing base-ten numbers without the usual binary floating-point approximation.
liveBook manning.com

Grokking Relational Database DesignA DECIMAL data type is an SQL fixed-point numeric type whose precision and scale control the represented number of digits.
liveBook manning.com

ScyllaDB in ActionDECIMAL is a ScyllaDB arbitrary-width decimal data type that represents values precisely.
liveBook manning.com

Python Workout: 50 ten-minute exercisesDecimal is a Python numeric class that provides decimal floating-point arithmetic with explicitly represented base-ten values.

Compare how 5 books explain Decimal →

Related concepts

floating-point arithmeticalternative to · Floating-point arithmetic is computation using finite-precision representations of real numbers, which can introduce rounding and range errors.
number typekind of · A number type is a programming-language or data-system type whose values represent numeric quantities and support defined numerical operations.
float64contrasts with · Float64 is a 64-bit floating-point numeric type, commonly represented using the IEEE 754 binary64 format.

This explainer was generated by Manning's knowledge graph from the text of PostgreSQL Mistakes and How to Avoid Them. The section links point to the parts of the book it draws on.