[feat] 新增 表结构操作

schema/schema.go

@@ -0,0 +1,59 @@
+package schema
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"git.fsdpf.net/go/db/v2"
+)
+
+type Schema interface {
+	// 判断表是否存在
+	TableExists(table string) (bool, error)
+	// 字段列
+	GetColumnListing(table string) ([]string, error)
+	// 创建表
+	CompileCreate(bp *Blueprint) []string
+	// 添加字段
+	CompileAdd(bp *Blueprint) []string
+	// 修改字段
+	CompileChange(bp *Blueprint) []string
+	// 删除表
+	CompileDrop(bp *Blueprint) []string
+	// 删除表, 先判断再删除
+	CompileDropIfExists(bp *Blueprint) []string
+	// 删除表, 删除列
+	CompileDropColumn(bp *Blueprint) []string
+	// 表重命名
+	CompileRename(bp *Blueprint) []string
+	// 生成SQL
+	GenerateSQL(sql string, args ...any) string
+}
+
+var (
+	dialects   = make(map[string]func(db *db.Database) Schema)
+	dialectsMu sync.RWMutex
+)
+
+func RegisterDialect(name string, sc func(db *db.Database) Schema) {
+	dialectsMu.Lock()
+	defer dialectsMu.Unlock()
+	lowerName := strings.ToLower(name)
+	dialects[lowerName] = sc
+}
+
+func DeregisterDialect(name string) {
+	dialectsMu.Lock()
+	defer dialectsMu.Unlock()
+	delete(dialects, strings.ToLower(name))
+}
+
+func GetSchemaDialect(db *db.Database) Schema {
+	name := strings.ToLower(db.Dialect())
+	if d, ok := dialects[name]; ok {
+		return d(db)
+	}
+
+	panic(fmt.Sprintf("Unsupported driver: %s", name))
+}