Use variadic parameters for DropColumns.

Also add some comments.

pkg/database/database.go

@@ -57,6 +57,7 @@ func Init(name, datasource string) error {
 	return nil
 }
 
+// Close database connection.
 func Close() {
 	db.Close()
 }

pkg/database/migrate/201402211147_github_enterprise_support.go

@@ -21,6 +21,6 @@ func (r *Rev3) Up(mg *MigrationDriver) error {
 }
 
 func (r *Rev3) Down(mg *MigrationDriver) error {
-	_, err := mg.DropColumns("settings", []string{"github_domain", "github_apiurl"})
+	_, err := mg.DropColumns("settings", "github_domain", "github_apiurl")
 	return err
 }

pkg/database/migrate/20140310104446_add_open_invitation_column.go

@@ -16,6 +16,6 @@ func (r *rev20140310104446) Up(mg *MigrationDriver) error {
 }
 
 func (r *rev20140310104446) Down(mg *MigrationDriver) error {
-	_, err := mg.DropColumns("settings", []string{"open_invitations"})
+	_, err := mg.DropColumns("settings", "open_invitations")
 	return err
 }

pkg/database/migrate/all.go

@@ -1,5 +1,9 @@
 package migrate
 
+// All is called to collect all migration scripts
+// and adds them to Revision list. New Revision
+// should be added here ordered by its revision
+// number.
 func (m *Migration) All() *Migration {
 
 	// List all migrations here

pkg/database/migrate/api.go

@@ -8,29 +8,56 @@ import (
 // Implementation details is specific for each database,
 // see migrate/sqlite.go for implementation reference.
 type Operation interface {
+
+	// CreateTable may be used to create a table named `tableName`
+	// with its columns specification listed in `args` as an array of string
 	CreateTable(tableName string, args []string) (sql.Result, error)
 
+	// RenameTable simply rename table from `tableName` to `newName`
 	RenameTable(tableName, newName string) (sql.Result, error)
 
+	// DropTable drops table named `tableName`
 	DropTable(tableName string) (sql.Result, error)
 
+	// AddColumn adds single new column to `tableName`, columnSpec is
+	// a standard column definition (column name included) which may looks like this:
+	//
+	//     mg.AddColumn("example", "email VARCHAR(255) UNIQUE")
+	//
+	// it's equivalent to:
+	//
+	//     mg.AddColumn("example", mg.T.String("email", UNIQUE))
+	//
 	AddColumn(tableName, columnSpec string) (sql.Result, error)
 
+	// ChangeColumn may be used to change the type of a column
+	// `newType` should always specify the column's new type even
+	// if the type is not meant to be change. Eg.
+	//
+	//     mg.ChangeColumn("example", "name", "VARCHAR(255) UNIQUE")
+	//
 	ChangeColumn(tableName, columnName, newType string) (sql.Result, error)
 
-	DropColumns(tableName string, columnsToDrop []string) (sql.Result, error)
+	// DropColumns drops a list of columns
+	DropColumns(tableName string, columnsToDrop ...string) (sql.Result, error)
 
+	// RenameColumns will rename columns listed in `columnChanges`
 	RenameColumns(tableName string, columnChanges map[string]string) (sql.Result, error)
 
+	// AddIndex adds index on `tableName` indexed by `columns`
 	AddIndex(tableName string, columns []string, flags ...string) (sql.Result, error)
 
+	// DropIndex drops index indexed by `columns` from `tableName`
 	DropIndex(tableName string, columns []string) (sql.Result, error)
 }
 
+// MigrationDriver drives migration script by injecting transaction object (*sql.Tx),
+// `Operation` implementation and column type helper.
 type MigrationDriver struct {
 	Operation
 	T  *columnType
 	Tx *sql.Tx
 }
 
+// DriverBuilder is a constructor for MigrationDriver
 type DriverBuilder func(tx *sql.Tx) *MigrationDriver

pkg/database/migrate/column_type.go

@@ -12,16 +12,20 @@ const (
 	AUTOINCREMENT
 	NULL
 	NOTNULL
-
-	TSTRING
-	TTEXT
 )
 
+// columnType will be injected to migration script
+// along with MigrationDriver. `AttrMap` is used to
+// defines distinct column's attribute between database
+// implementation. e.g. 'AUTOINCREMENT' in sqlite and
+// 'AUTO_INCREMENT' in mysql.
 type columnType struct {
 	Driver  string
 	AttrMap map[int]string
 }
 
+// defaultMap defines default values for column's attribute
+// lookup.
 var defaultMap = map[int]string{
 	UNIQUE:        "UNIQUE",
 	PRIMARYKEY:    "PRIMARY KEY",
@@ -30,34 +34,45 @@ var defaultMap = map[int]string{
 	NOTNULL:       "NOT NULL",
 }
 
+// Integer returns column definition for INTEGER typed column.
+// Additional attributes may be specified as string or predefined key
+// listed in defaultMap.
 func (c *columnType) Integer(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s INTEGER %s", colName, c.parseAttr(spec))
 }
 
+// String returns column definition for VARCHAR(255) typed column.
 func (c *columnType) String(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s VARCHAR(255) %s", colName, c.parseAttr(spec))
 }
 
+// Text returns column definition for TEXT typed column.
 func (c *columnType) Text(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s TEXT %s", colName, c.parseAttr(spec))
 }
 
+// Blob returns column definition for BLOB typed column
 func (c *columnType) Blob(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s BLOB %s", colName, c.parseAttr(spec))
 }
 
+// Timestamp returns column definition for TIMESTAMP typed column
 func (c *columnType) Timestamp(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s TIMESTAMP %s", colName, c.parseAttr(spec))
 }
 
+// Bool returns column definition for BOOLEAN typed column
 func (c *columnType) Bool(colName string, spec ...interface{}) string {
 	return fmt.Sprintf("%s BOOLEAN %s", colName, c.parseAttr(spec))
 }
 
+// Varchar returns column definition for VARCHAR typed column.
+// column's max length is specified as `length`.
 func (c *columnType) Varchar(colName string, length int, spec ...interface{}) string {
 	return fmt.Sprintf("%s VARCHAR(%d) %s", colName, length, c.parseAttr(spec))
 }
 
+// attr returns string representation of column attribute specified as key for defaultMap.
 func (c *columnType) attr(flag int) string {
 	if v, ok := c.AttrMap[flag]; ok {
 		return v
@@ -65,6 +80,8 @@ func (c *columnType) attr(flag int) string {
 	return defaultMap[flag]
 }
 
+// parseAttr reflects spec value for its type and returns the string
+// representation returned by `attr`
 func (c *columnType) parseAttr(spec []interface{}) string {
 	var attrs []string
 	for _, v := range spec {

pkg/database/migrate/migrate.go

@@ -1,24 +1,3 @@
-// Usage
-//    migrate.To(2)
-//    	.Add(Version_1)
-//    	.Add(Version_2)
-//    	.Add(Version_3)
-//    	.Exec(db)
-//
-//    migrate.ToLatest()
-//    	.Add(Version_1)
-//    	.Add(Version_2)
-//    	.Add(Version_3)
-//    	.SetDialect(migrate.MySQL)
-//    	.Exec(db)
-//
-//    migrate.ToLatest()
-//    	.Add(Version_1)
-//    	.Add(Version_2)
-//    	.Add(Version_3)
-//		.Backup(path)
-//		.Exec()
-
 package migrate
 
 import (
@@ -72,7 +51,7 @@ func (m *Migration) Add(rev ...Revision) *Migration {
 	return m
 }
 
-// Execute the full list of migrations.
+// Migrate executes the full list of migrations.
 func (m *Migration) Migrate() error {
 	var target int64
 	if len(m.revs) > 0 {
@@ -84,7 +63,7 @@ func (m *Migration) Migrate() error {
 	return m.MigrateTo(target)
 }
 
-// Execute all database migration until
+// MigrateTo executes all database migration until
 // you are at the specified revision number.
 // If the revision number is less than the
 // current revision, then we will downgrade.

pkg/database/migrate/mysql.go

@@ -40,7 +40,7 @@ func (m *mysqlDriver) ChangeColumn(tableName, columnName, newSpecs string) (sql.
 	return m.Tx.Exec(fmt.Sprintf("ALTER TABLE %s MODIFY %s %s", tableName, columnName, newSpecs))
 }
 
-func (m *mysqlDriver) DropColumns(tableName string, columnsToDrop []string) (sql.Result, error) {
+func (m *mysqlDriver) DropColumns(tableName string, columnsToDrop ...string) (sql.Result, error) {
 	for k, v := range columnsToDrop {
 		columnsToDrop[k] = fmt.Sprintf("DROP %s", v)
 	}

pkg/database/migrate/postgresql.go

@@ -36,7 +36,7 @@ func (p *postgresqlDriver) ChangeColumn(tableName, columnName, newSpecs string)
 	return nil, errors.New("not implemented yet")
 }
 
-func (p *postgresqlDriver) DropColumns(tableName string, columnsToDrop []string) (sql.Result, error) {
+func (p *postgresqlDriver) DropColumns(tableName string, columnsToDrop ...string) (sql.Result, error) {
 	return nil, errors.New("not implemented yet")
 }
 

pkg/database/migrate/sqlite.go

@@ -91,7 +91,7 @@ func (s *sqliteDriver) ChangeColumn(tableName, columnName, newType string) (sql.
 
 }
 
-func (s *sqliteDriver) DropColumns(tableName string, columnsToDrop []string) (sql.Result, error) {
+func (s *sqliteDriver) DropColumns(tableName string, columnsToDrop ...string) (sql.Result, error) {
 	var err error
 	var result sql.Result
 

pkg/database/migrate/sqlite_test.go

@@ -89,7 +89,7 @@ func (r *revision3) Up(mg *MigrationDriver) error {
 }
 
 func (r *revision3) Down(mg *MigrationDriver) error {
-	_, err := mg.DropColumns("samples", []string{"num", "url"})
+	_, err := mg.DropColumns("samples", "num", "url")
 	return err
 }
 
@@ -128,7 +128,7 @@ func (r *revision4) Revision() int64 {
 type revision5 struct{}
 
 func (r *revision5) Up(mg *MigrationDriver) error {
-	_, err := mg.AddIndex("samples", []string{"url", "name"}, "")
+	_, err := mg.AddIndex("samples", []string{"url", "name"})
 	return err
 }
 
@@ -170,7 +170,7 @@ func (r *revision6) Revision() int64 {
 type revision7 struct{}
 
 func (r *revision7) Up(mg *MigrationDriver) error {
-	_, err := mg.DropColumns("samples", []string{"host", "num"})
+	_, err := mg.DropColumns("samples", "host", "num")
 	return err
 }
 
@@ -200,7 +200,7 @@ func (r *revision8) Up(mg *MigrationDriver) error {
 }
 
 func (r *revision8) Down(mg *MigrationDriver) error {
-	_, err := mg.DropColumns("samples", []string{"repo", "repo_id"})
+	_, err := mg.DropColumns("samples", "repo", "repo_id")
 	return err
 }