Intersperses proper Ecto column references between values to be queried.

Examples

intersperse_column_refs(["post"], "title")
# => [s.title, "post"]

intersperse_column_refs(["best", "post"], "title")
# => [s.title, "best", s.title, "post"]

Background

Ecto queries support string query fragments, but fields referenced in these fragments need to specifically reference fields, or you will get “Ambiguous column” errors for some queries.

In other words:

# Good
where(query, [s], fragment("lower(?) = lower(?)", s.title, "post")

# Bad
where(query, [s], fragment("lower(title) = lower(?)", "post"))

Interpolating s.title into the fragment arguments ensures that joined tables which also have the title column will not conflict.

See Ecto.Query.API.fragment/1 for more details.

This macro allows a simple creation of encoders using a simple DSL.

Example:

encoder "equals", "does not equal", "column = ?", &(&1)

In this example, a comparator and its reverse are passed in followed by an expression where “column” is substituted for the actual column name from the struct. The final argument is a function (which is not necessary in this case since it is the default value) that takes the raw value being passed in and returns the transformed value to be injected as a value into the fragment expression.