Supported Go types and their format¶

Supported Go types¶

SQLair supports the following types:

In input expressions:
- structs
- maps
- slices
In output expressions:
- structs
- maps

All types used with SQLair must be named so they can be referenced in the query.

Type format¶

Structs¶

For a struct to be usable by SQLair, all struct fields that correspond to a database column must be tagged with a db tag containing the column name. These fields must be public (i.e. start with a capital letter), though the struct itself does not have to be. Any fields without a tag will be ignored.

If a struct contains an embedded struct then SQLair will treat the fields of the embedded structs as if they were fields in the parent struct.

For example:

type Person struct {
    Name    string  `db:"name"`
    ID      int     `db:"id_number"`
    DoB     string  `db:"date_of_birth"`
    Weight  int
    height  int
}

In this example the Weight and height fields will be ignored by SQLair.

The “omitempty” keyword¶

In a struct tag, the omitempty keyword tells SQLair to omit the column from an insert operation if the value in the corresponding struct field zeroed.

This is useful if the content of the column is generated by the database, e.g. if it has an auto-increment directive.

To add the omitempty keyword, write it in the db tag after the column name.

For example:

type Address struct {
    ID   string `db:"id, omitempty"`
    City string `db:"city"`
}

Insert syntax

Maps¶

Named maps can be used with SQLair and must have a key with a base type of string. This is because SQLair uses the column names as keys when reading from and writing to the map. The value type of the map can be anything.

For example:

type Cols map[string]int

sqlair.M¶

For convenience, SQLair provides a named map type sqlair.M which has the type map[string]any.

Slices¶

Named slices can only be used as inputs and will expand into a comma separated list of input placeholders for each value in the slice. The slice must be named and can be of any type.

For example:

type Names []string

sqlair.S¶

For convenience, SQLair provides a named slice type sqlair.S which has the type []any.