sqlboiler/bdb/interface.go
2016-09-06 00:41:12 +10:00

114 lines
3 KiB
Go

// Package bdb supplies the sql(b)oiler (d)ata(b)ase abstractions.
package bdb
import "github.com/pkg/errors"
// Interface for a database driver. Functionality required to support a specific
// database type (eg, MySQL, Postgres etc.)
type Interface interface {
TableNames(whitelist, exclude []string) ([]string, error)
Columns(tableName string) ([]Column, error)
PrimaryKeyInfo(tableName string) (*PrimaryKey, error)
ForeignKeyInfo(tableName string) ([]ForeignKey, error)
// TranslateColumnType takes a Database column type and returns a go column type.
TranslateColumnType(Column) Column
// UseLastInsertID should return true if the driver is capable of using
// the sql.Exec result's LastInsertId
UseLastInsertID() bool
// Open the database connection
Open() error
// Close the database connection
Close()
}
// Tables returns the metadata for all tables, minus the tables
// specified in the exclude slice.
func Tables(db Interface, whitelist, exclude []string) ([]Table, error) {
var err error
names, err := db.TableNames(whitelist, exclude)
if err != nil {
return nil, errors.Wrap(err, "unable to get table names")
}
var tables []Table
for _, name := range names {
t := Table{Name: name}
if t.Columns, err = db.Columns(name); err != nil {
return nil, errors.Wrapf(err, "unable to fetch table column info (%s)", name)
}
for i, c := range t.Columns {
t.Columns[i] = db.TranslateColumnType(c)
}
if t.PKey, err = db.PrimaryKeyInfo(name); err != nil {
return nil, errors.Wrapf(err, "unable to fetch table pkey info (%s)", name)
}
if t.FKeys, err = db.ForeignKeyInfo(name); err != nil {
return nil, errors.Wrapf(err, "unable to fetch table fkey info (%s)", name)
}
setIsJoinTable(&t)
tables = append(tables, t)
}
// Relationships have a dependency on foreign key nullability.
for i := range tables {
tbl := &tables[i]
setForeignKeyConstraints(tbl, tables)
}
for i := range tables {
tbl := &tables[i]
setRelationships(tbl, tables)
}
return tables, nil
}
// setIsJoinTable if there are:
// A composite primary key involving two columns
// Both primary key columns are also foreign keys
func setIsJoinTable(t *Table) {
if t.PKey == nil || len(t.PKey.Columns) != 2 || len(t.FKeys) < 2 {
return
}
for _, c := range t.PKey.Columns {
found := false
for _, f := range t.FKeys {
if c == f.Column {
found = true
break
}
}
if !found {
return
}
}
t.IsJoinTable = true
}
func setForeignKeyConstraints(t *Table, tables []Table) {
for i, fkey := range t.FKeys {
localColumn := t.GetColumn(fkey.Column)
foreignTable := GetTable(tables, fkey.ForeignTable)
foreignColumn := foreignTable.GetColumn(fkey.ForeignColumn)
t.FKeys[i].Nullable = localColumn.Nullable
t.FKeys[i].Unique = localColumn.Unique
t.FKeys[i].ForeignColumnNullable = foreignColumn.Nullable
t.FKeys[i].ForeignColumnUnique = foreignColumn.Unique
}
}
func setRelationships(t *Table, tables []Table) {
t.ToManyRelationships = toManyRelationships(*t, tables)
}