Files
gocqlx/qb/delete.go
Michał Matczuk 2afe71e2b9 qb: cmp
2017-07-28 12:11:39 +02:00

94 lines
1.8 KiB
Go

package qb
// DELETE reference:
// http://docs.datastax.com/en/dse/5.1/cql/cql/cql_reference/cql_commands/cqlDelete.html
import (
"bytes"
"errors"
"fmt"
"time"
)
type DeleteBuilder struct {
table string
columns columns
using using
where where
_if _if
exists bool
}
// Delete returns a new DeleteBuilder with the given table name.
func Delete(table string) *DeleteBuilder {
return &DeleteBuilder{
table: table,
}
}
func (b *DeleteBuilder) ToCql() (stmt string, names []string, err error) {
if b.table == "" {
err = errors.New("delete statements must specify a table")
return
}
if len(b.where) == 0 {
err = fmt.Errorf("delete statements must have at least one WHERE clause")
return
}
cql := bytes.Buffer{}
cql.WriteString("DELETE ")
if len(b.columns) > 0 {
b.columns.writeCql(&cql)
cql.WriteByte(' ')
}
cql.WriteString("FROM ")
cql.WriteString(b.table)
cql.WriteByte(' ')
b.using.writeCql(&cql)
names = append(names, b.where.writeCql(&cql)...)
names = append(names, b._if.writeCql(&cql)...)
if b.exists {
cql.WriteString("IF EXISTS ")
}
stmt = cql.String()
return
}
// From sets the table to be deleted from.
func (b *DeleteBuilder) From(table string) *DeleteBuilder {
b.table = table
return b
}
// Columns adds delete columns to the query.
func (b *DeleteBuilder) Columns(columns ...string) *DeleteBuilder {
b.columns = append(b.columns, columns...)
return b
}
func (b *DeleteBuilder) Timestamp(t time.Time) *DeleteBuilder {
b.using.timestamp = t
return b
}
func (b *DeleteBuilder) Where(w ...Cmp) *DeleteBuilder {
b.where = append(b.where, w...)
return b
}
func (b *DeleteBuilder) If(w ...Cmp) *DeleteBuilder {
b._if = append(b._if, w...)
return b
}
func (b *DeleteBuilder) Existing() *DeleteBuilder {
b.exists = true
return b
}