Table Column with Default Expression

[billy1624]

Motivation

• Currently, we support column with default value but not default expression
• Having default expression in column such as timestamp / datetime is very common, e.g. CURRENT_TIMESTAMP as the default expression

Proposed Solutions

• ColumnSpec::Default(Value) should be changed to holding SimpleExpr, i.e. ColumnSpec::Default(SimpleExpr) https://github.com/SeaQL/sea-query/blob/6c9527ae08e32c55490ae510be41f646e030c2a2/src/table/column.rs#L48-L58
• Keep the old default method and introduce a new method called default_expr which take any Into<SimpleExpr> https://github.com/SeaQL/sea-query/blob/6c9527ae08e32c55490ae510be41f646e030c2a2/src/table/column.rs#L142-L149

[ikrivosheev]

@billy1624, hello! I will do this.

[billy1624]

Thanks! @ikrivosheev

[billy1624]

Related Discussion:

• https://github.com/SeaQL/sea-query/discussions/346

[ikrivosheev]

@billy1624 what do you think about new Enum for table? We only need some variants from SimpleExpr

1. FuncionCall
2. Value
3. Custom

[ikrivosheev]

No, bad ideas... We need to split QueryBuilder. For unavailable operations panic.

[billy1624]

Hey @ikrivosheev, sorry for the delay.

@billy1624 what do you think about new Enum for table? We only need some variants from SimpleExpr

Do you mean introducing a new Enum for the "Default Value" of a column? https://github.com/SeaQL/sea-query/blob/63e18941fad55e391e4abb1316fd81e7a7768f91/src/table/column.rs#L51-L61

pub enum ColumnSpec {
...
    Default(DefaultValue)
...
}

// I just makeup the name, feel free to rename it :)
pub enum DefaultValue {
    Func(Function),
    Value(Value),
    Custom(String),
}

Something like this?

[ikrivosheev]

Hey @ikrivosheev, sorry for the delay.

@billy1624 what do you think about new Enum for table? We only need some variants from SimpleExpr

Do you mean introducing a new Enum for the "Default Value" of a column?

https://github.com/SeaQL/sea-query/blob/63e18941fad55e391e4abb1316fd81e7a7768f91/src/table/column.rs#L51-L61

pub enum ColumnSpec {
...
    Default(DefaultValue)
...
}

// I just makeup the name, feel free to rename it :)
pub enum DefaultValue {
    Func(Function),
    Value(Value),
    Custom(String),
}

Something like this?

Yes

[ikrivosheev]

@billy1624 @tyt2y3 what do you think about custom Enum?

[tyt2y3]

1. I think we should rename the old default to default_value and the new default is an alias of default_expr
2. Yes I think having a dedicated DefaultColumnExpr is a good idea

[ikrivosheev]

@tyt2y3 @billy1624 hello! I have made several attempts and understand that is better to use SimpleExpr instead create DefaultColumnExpr

[tyt2y3]

I have no objection to either

[billy1624]

Hello @ikrivosheev, are you working on this?