Rewrite enum and text casting

[billy1624]

PR Info

• Closes fn column() also handle enum type #960

Adds

• QuerySelect::column method also handle enum type

Changes

• Refactor all enum and text casting in SeaORM

[tyt2y3]

Same here, I might have lost the context, but why are we passing enum name around as String? Can we pass around DynIden instead?

[billy1624]

The String comes from ColumnType::Enum

sea-orm/src/entity/column.rs

Line 81 in 87f7891

Enum(String, Vec<String>),

I rewrite it into F: Fn(Expr, DynIden) -> SimpleExpr, but still, we need to wrap the String as DynIden like SeaRc::new(Alias::new(enum_name))

[tyt2y3]

Um... I think we should have used an Iden here. Second question is, how often is this ColumnType object being cloned? If it is being cloned frequently then we'd better Arc it. At the very least I think a named struct serves as a better documentation:

EnumDef {
    name: DynIden,
    variants: Vec<DynIden>,
}