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delete.go
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delete.go
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package sqlbuilder
// DeleteBuilder is the Buildable interface wrapping of Delete
type DeleteBuilder interface {
Where(cond Condition) DeleteBuilder
ToSql() (query string, args []interface{}, err error)
privateDelete()
}
// DeleteStatement represents a DELETE statement.
type DeleteStatement struct {
from Table
where Condition
err error
dialect Dialect
}
// Delete returns new DELETE statement. The table is Table object to delete from.
func Delete(from Table) DeleteBuilder {
return deleteFn(from, dialect())
}
func deleteFn(from Table, d Dialect) *DeleteStatement {
if d == nil {
d = dialect()
}
if from == nil {
return &DeleteStatement{
err: newError("from is nil."),
}
}
if _, ok := from.(*table); !ok {
return &DeleteStatement{
err: newError("CreateTable can use only natural table."),
}
}
return &DeleteStatement{
from: from,
dialect: d,
}
}
func (b *DeleteStatement) privateDelete() {
// nop
}
// Where sets WHERE clause. cond is filter condition.
func (b *DeleteStatement) Where(cond Condition) DeleteBuilder {
if b.err != nil {
return b
}
for _, col := range cond.columns() {
if !b.from.hasColumn(col) {
b.err = newError("column not found in FROM")
return b
}
}
b.where = cond
return b
}
// ToSql generates query string, placeholder arguments, and returns err on errors.
func (b *DeleteStatement) ToSql() (query string, args []interface{}, err error) {
bldr := newBuilder(b.dialect)
defer func() {
query, args, err = bldr.Query(), bldr.Args(), bldr.Err()
}()
if b.err != nil {
bldr.SetError(b.err)
return
}
bldr.Append("DELETE FROM ")
bldr.AppendItem(b.from)
if b.where != nil {
bldr.Append(" WHERE ")
bldr.AppendItem(b.where)
}
return
}