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table_foreign_key.go
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/
table_foreign_key.go
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package gosql
import "strings"
// FOREIGN KEY ( column_name [, ... ] ) REFERENCES reftable [ ( refcolumn [, ... ] ) ]
//
// [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ] [ ON DELETE referential_action ] [ ON UPDATE referential_action ] }
type foreignKey struct {
// columns
columns expression
// reference
referencesColumn referencesColumn
}
// Columns get columns
func (f *foreignKey) Columns() *expression {
return &f.columns
}
// Columns get columns
func (f *foreignKey) Column(col ...string) *foreignKey {
f.columns.Add(col...)
return f
}
// References get references
func (f *foreignKey) References() *referencesColumn {
return &f.referencesColumn
}
// String render foreign key
func (f *foreignKey) String() string {
if f.IsEmpty() {
return ""
}
b := strings.Builder{}
b.WriteString(" FOREIGN KEY")
if f.columns.Len() > 0 {
b.WriteString(" (" + f.columns.String(", ") + ")")
}
if !f.referencesColumn.IsEmpty() {
b.WriteString(" " + f.referencesColumn.String())
}
return b.String()
}
// IsEmpty is foreign key empty
func (f *foreignKey) IsEmpty() bool {
return f == nil || (f.columns.Len() == 0 && f.referencesColumn.IsEmpty())
}