func (b *Backend) AlterField(db *sql.DB, m driver.Model, table *sql.Table, oldField *sql.Field, newField *sql.Field) error {
fsql, cons, err := newField.SQL(db, m, table)
if err != nil {
return err
}
tableName := db.QuoteIdentifier(m.Table())
if _, err = db.Exec(fmt.Sprintf("ALTER TABLE %s CHANGE COLUMN %s %s", tableName, db.QuoteIdentifier(oldField.Name), fsql)); err != nil {
return err
}
for _, c := range cons {
if _, err = db.Exec(fmt.Sprintf("ALTER TABLE %s ADD CONSTRAINT %s", tableName, c)); err != nil {
return err
}
}
return err
}
func (b *Backend) AddFields(db *sql.DB, m driver.Model, prevTable *sql.Table, newTable *sql.Table, fields []*sql.Field) error {
rewrite := false
for _, v := range fields {
if !b.canAddField(v) {
rewrite = true
break
}
}
if rewrite {
name := db.QuoteIdentifier(m.Table())
tmpName := fmt.Sprintf("%s_%s", m.Table(), stringutil.Random(8))
quotedTmpName := db.QuoteIdentifier(tmpName)
createSql, err := newTable.SQL(db, b, m, tmpName)
if err != nil {
return err
}
if _, err := db.Exec(createSql); err != nil {
return err
}
fieldNames := generic.Map(prevTable.Fields, func(f *sql.Field) string { return f.Name }).([]string)
// The previous table might have fields that we're not part
// of the new table.
fieldSet := make(map[string]bool)
for _, v := range newTable.Fields {
fieldSet[v.Name] = true
}
fieldNames = generic.Filter(fieldNames, func(n string) bool { return fieldSet[n] }).([]string)
sqlFields := strings.Join(generic.Map(fieldNames, db.QuoteIdentifier).([]string), ", ")
copySql := fmt.Sprintf("INSERT INTO %s (%s) SELECT %s FROM %s", quotedTmpName, sqlFields, sqlFields, name)
if _, err := db.Exec(copySql); err != nil {
return err
}
if _, err := db.Exec(fmt.Sprintf("DROP TABLE %s", name)); err != nil {
return err
}
if _, err := db.Exec(fmt.Sprintf("ALTER TABLE %s RENAME TO %s", quotedTmpName, name)); err != nil {
return err
}
return nil
}
return b.SqlBackend.AddFields(db, m, prevTable, newTable, fields)
}
func (b *Backend) DefineField(db *sql.DB, m driver.Model, table *sql.Table, field *sql.Field) (string, []string, error) {
def, cons, err := b.SqlBackend.DefineField(db, m, table, field)
if err != nil {
return "", nil, err
}
if ref := field.Constraint(sql.ConstraintForeignKey); ref != nil {
if pos := strings.Index(def, " REFERENCES"); pos >= 0 {
def = def[:pos]
}
refTable := ref.References.Table()
refField := ref.References.Field()
fkName := db.QuoteIdentifier(fmt.Sprintf("%s_%s_%s_%s", m.Table(), field.Name, refTable, refField))
cons = append(cons, fmt.Sprintf("FOREIGN KEY %s(%s) REFERENCES %s(%s)", fkName, db.QuoteIdentifier(field.Name),
db.QuoteIdentifier(refTable), db.QuoteIdentifier(refField)))
}
return strings.Replace(def, "AUTOINCREMENT", "AUTO_INCREMENT", -1), cons, nil
}
