Add support for DELETE statements.

sqlbuilder/delete_statement.go

@@ -0,0 +1,70 @@
+package sqlbuilder
+
+import (
+	"bytes"
+	"database/sql"
+	"github.com/dropbox/godropbox/errors"
+	"github.com/sub0zero/go-sqlbuilder/types"
+)
+
+type DeleteStatement interface {
+	Statement
+
+	WHERE(expression BoolExpression) DeleteStatement
+}
+
+func newDeleteStatement(table WritableTable) DeleteStatement {
+	return &deleteStatementImpl{
+		table: table,
+	}
+}
+
+type deleteStatementImpl struct {
+	table WritableTable
+	where BoolExpression
+	order *listClause
+}
+
+func (u *deleteStatementImpl) Query(db types.Db, destination interface{}) error {
+	return Query(u, db, destination)
+}
+
+func (u *deleteStatementImpl) Execute(db types.Db) (res sql.Result, err error) {
+	return Execute(u, db)
+}
+
+func (d *deleteStatementImpl) WHERE(expression BoolExpression) DeleteStatement {
+	d.where = expression
+	return d
+}
+
+func (d *deleteStatementImpl) String() (sql string, err error) {
+	buf := new(bytes.Buffer)
+	_, _ = buf.WriteString("DELETE FROM ")
+
+	if d.table == nil {
+		return "", errors.Newf("nil tableName.  Generated sql: %s", buf.String())
+	}
+
+	if err = d.table.SerializeSql(buf); err != nil {
+		return
+	}
+
+	if d.where == nil {
+		return "", errors.Newf("Deleting without a WHERE clause.  Generated sql: %s", buf.String())
+	}
+
+	_, _ = buf.WriteString(" WHERE ")
+	if err = d.where.SerializeSql(buf); err != nil {
+		return
+	}
+
+	if d.order != nil {
+		_, _ = buf.WriteString(" ORDER BY ")
+		if err = d.order.SerializeSql(buf); err != nil {
+			return
+		}
+	}
+
+	return buf.String() + ";", nil
+}