1. 实现配置文件解析

2. 实现数据库连接

vendor/gorm.io/gorm/migrator.go

@@ -0,0 +1,111 @@
+package gorm
+
+import (
+	"reflect"
+
+	"gorm.io/gorm/clause"
+	"gorm.io/gorm/schema"
+)
+
+// Migrator returns migrator
+func (db *DB) Migrator() Migrator {
+	tx := db.getInstance()
+
+	// apply scopes to migrator
+	for len(tx.Statement.scopes) > 0 {
+		tx = tx.executeScopes()
+	}
+
+	return tx.Dialector.Migrator(tx.Session(&Session{}))
+}
+
+// AutoMigrate run auto migration for given models
+func (db *DB) AutoMigrate(dst ...interface{}) error {
+	return db.Migrator().AutoMigrate(dst...)
+}
+
+// ViewOption view option
+type ViewOption struct {
+	Replace     bool   // If true, exec `CREATE`. If false, exec `CREATE OR REPLACE`
+	CheckOption string // optional. e.g. `WITH [ CASCADED | LOCAL ] CHECK OPTION`
+	Query       *DB    // required subquery.
+}
+
+// ColumnType column type interface
+type ColumnType interface {
+	Name() string
+	DatabaseTypeName() string                 // varchar
+	ColumnType() (columnType string, ok bool) // varchar(64)
+	PrimaryKey() (isPrimaryKey bool, ok bool)
+	AutoIncrement() (isAutoIncrement bool, ok bool)
+	Length() (length int64, ok bool)
+	DecimalSize() (precision int64, scale int64, ok bool)
+	Nullable() (nullable bool, ok bool)
+	Unique() (unique bool, ok bool)
+	ScanType() reflect.Type
+	Comment() (value string, ok bool)
+	DefaultValue() (value string, ok bool)
+}
+
+type Index interface {
+	Table() string
+	Name() string
+	Columns() []string
+	PrimaryKey() (isPrimaryKey bool, ok bool)
+	Unique() (unique bool, ok bool)
+	Option() string
+}
+
+// TableType table type interface
+type TableType interface {
+	Schema() string
+	Name() string
+	Type() string
+	Comment() (comment string, ok bool)
+}
+
+// Migrator migrator interface
+type Migrator interface {
+	// AutoMigrate
+	AutoMigrate(dst ...interface{}) error
+
+	// Database
+	CurrentDatabase() string
+	FullDataTypeOf(*schema.Field) clause.Expr
+	GetTypeAliases(databaseTypeName string) []string
+
+	// Tables
+	CreateTable(dst ...interface{}) error
+	DropTable(dst ...interface{}) error
+	HasTable(dst interface{}) bool
+	RenameTable(oldName, newName interface{}) error
+	GetTables() (tableList []string, err error)
+	TableType(dst interface{}) (TableType, error)
+
+	// Columns
+	AddColumn(dst interface{}, field string) error
+	DropColumn(dst interface{}, field string) error
+	AlterColumn(dst interface{}, field string) error
+	MigrateColumn(dst interface{}, field *schema.Field, columnType ColumnType) error
+	// MigrateColumnUnique migrate column's UNIQUE constraint, it's part of MigrateColumn.
+	MigrateColumnUnique(dst interface{}, field *schema.Field, columnType ColumnType) error
+	HasColumn(dst interface{}, field string) bool
+	RenameColumn(dst interface{}, oldName, field string) error
+	ColumnTypes(dst interface{}) ([]ColumnType, error)
+
+	// Views
+	CreateView(name string, option ViewOption) error
+	DropView(name string) error
+
+	// Constraints
+	CreateConstraint(dst interface{}, name string) error
+	DropConstraint(dst interface{}, name string) error
+	HasConstraint(dst interface{}, name string) bool
+
+	// Indexes
+	CreateIndex(dst interface{}, name string) error
+	DropIndex(dst interface{}, name string) error
+	HasIndex(dst interface{}, name string) bool
+	RenameIndex(dst interface{}, oldName, newName string) error
+	GetIndexes(dst interface{}) ([]Index, error)
+}