Numeric and decimal support

Numeric and decimal support

The Go language does not have a standard decimal type. pgx supports the PostgreSQL numeric type out of the box. However, in the absence of a proper Go type it can only be used when translated to a float64 or string. This is obviously not ideal.

The recommended solution is to use the github.com/shopspring/decimal package. pgx has support for integrating with this package, but to avoid a mandatory external dependency the integration is in a separate package.

To use it add the following line to your imports:

shopspring "github.com/jackc/pgtype/ext/shopspring-numeric"

Then run the following to register the data type with a connection:

conn.ConnInfo().RegisterDataType(pgtype.DataType{
  Value: &shopspring.Numeric{},
  Name:  "numeric",
  OID:   pgtype.NumericOID,
})

If you are using pgxpool the previous command should be run in an AfterConnect hook to ensure it is available on every connection.

You will now be able to use a decimal.Decimal as an query argument or scan destination.