1. 实现配置文件解析

2. 实现数据库连接

vendor/gorm.io/gorm/clause/clause.go

@@ -0,0 +1,89 @@
+package clause
+
+// Interface clause interface
+type Interface interface {
+	Name() string
+	Build(Builder)
+	MergeClause(*Clause)
+}
+
+// ClauseBuilder clause builder, allows to customize how to build clause
+type ClauseBuilder func(Clause, Builder)
+
+type Writer interface {
+	WriteByte(byte) error
+	WriteString(string) (int, error)
+}
+
+// Builder builder interface
+type Builder interface {
+	Writer
+	WriteQuoted(field interface{})
+	AddVar(Writer, ...interface{})
+	AddError(error) error
+}
+
+// Clause
+type Clause struct {
+	Name                string // WHERE
+	BeforeExpression    Expression
+	AfterNameExpression Expression
+	AfterExpression     Expression
+	Expression          Expression
+	Builder             ClauseBuilder
+}
+
+// Build build clause
+func (c Clause) Build(builder Builder) {
+	if c.Builder != nil {
+		c.Builder(c, builder)
+	} else if c.Expression != nil {
+		if c.BeforeExpression != nil {
+			c.BeforeExpression.Build(builder)
+			builder.WriteByte(' ')
+		}
+
+		if c.Name != "" {
+			builder.WriteString(c.Name)
+			builder.WriteByte(' ')
+		}
+
+		if c.AfterNameExpression != nil {
+			c.AfterNameExpression.Build(builder)
+			builder.WriteByte(' ')
+		}
+
+		c.Expression.Build(builder)
+
+		if c.AfterExpression != nil {
+			builder.WriteByte(' ')
+			c.AfterExpression.Build(builder)
+		}
+	}
+}
+
+const (
+	PrimaryKey   string = "~~~py~~~" // primary key
+	CurrentTable string = "~~~ct~~~" // current table
+	Associations string = "~~~as~~~" // associations
+)
+
+var (
+	currentTable  = Table{Name: CurrentTable}
+	PrimaryColumn = Column{Table: CurrentTable, Name: PrimaryKey}
+)
+
+// Column quote with name
+type Column struct {
+	Table string
+	Name  string
+	Alias string
+	Raw   bool
+}
+
+// Table quote with name
+type Table struct {
+	Name  string
+	Alias string
+	Raw   bool
+}