//
// Create an index given the name (index) and a list of field positions
// used to create a composite key.
//
// nilFirst specifies if nil values should sort first (lowest possible value) or last (highest possible value)
//
// The field position should corrispond to the entries in DataRecord ToFieldList() and FromFieldList()
//
func (t *Table) CreateIndex(index string, nilFirst bool, fields ...uint64) error {
db := (*bolt.DB)(t.d)
err := db.Update(func(tx *bolt.Tx) error {
b := tx.Bucket(schema(t.name))
if b == nil {
return NO_TABLE
}
b1, err := typedbuffer.Encode(nilFirst)
if err != nil {
return BAD_VALUES
}
b2, err := typedbuffer.Encode(fields)
if err != nil {
return BAD_VALUES
}
enc := append(b1, b2...)
if err := b.Put([]byte(index), enc); err != nil {
return err
}
if _, err := tx.CreateBucket(indices(index)); err != nil {
return err
}
return nil
})
if err == nil {
t.indices[index] = indexinfo{
nilFirst: nilFirst,
iplist: makeIndexPos(fields),
}
}
return err
}
//
// Delete a record from the table, given the index and the key
//
func (t *Table) Delete(index string, key DataRecord) error {
db := (*bolt.DB)(t.d)
err := db.Update(func(tx *bolt.Tx) error {
b := tx.Bucket(indices(index))
if b == nil {
return NO_INDEX
}
info := t.indices[index]
sk, _, err := info.marshalKeyValue(key.ToFieldList())
if err != nil {
return err
}
if sk == nil {
return NO_KEY
}
c := b.Cursor()
k, v := c.Seek(sk)
// Seek will return the next key if there is no match
// so make sure we check we got the right record
if bytes.Equal(sk, k) {
if err := c.Delete(); err != nil {
return err
}
fields, err := info.unmarshalKeyValue(k, v)
if err != nil {
return err
}
for i, info := range t.indices {
if i == index {
// already done
continue
}
b := tx.Bucket(indices(i))
if b == nil {
continue
}
// could use marshalKeyValue() instead
vkey := make([]interface{}, len(info.iplist))
for _, ip := range info.iplist {
vkey[ip.pos] = fields[ip.field]
}
dkey, err := typedbuffer.Encode(vkey...)
if err != nil {
return err
}
if err := b.Delete(dkey); err != nil {
return err
}
}
}
return nil
})
return err
}
