CHANGELOG.md

@@ -1,10 +1,6 @@
 # 变更记录 - @go/db
 
-## [1.5.3] - 2026-06-08
+## [1.5.1] - 2026-06-04
-- **新增**: `SetConfig(name, setting string)` 方法，支持动态配置数据库连接（不依赖配置文件），方便通过别名获取连接。
-- **优化**: 重构配置加载逻辑，支持动态配置与 `config/db.yaml` 配置文件配置共存。
-
-## [1.5.2] - 2026-06-05
 - **架构重构: 两阶段 (Two-Pass) 索引命名生成**:
   - 重构了 `CheckTable` 中的 Schema 同步逻辑，从“边解析边生成”改为两阶段处理。现在多列联合索引（无论是 Unique, Index 还是 Fulltext）的名字会根据包含的**字段名称自动拼接生成**（如 `uk_user_name_phone`），替代了以前难以溯源的分组号（如 `uk_user_1`），极大提升了 DBA 在数据库维护时的可读性与直观性。
   - **超长防断机制**: 当生成的索引名称超过 60 个字符时，自动进行截断，并在末尾追加原完整名称的 6 位 MD5 Hash，完美规避了各种 RDBMS 对标识符 64 字符长度限制引发的建表错误。

DB.go

@@ -412,59 +412,6 @@ func Begin() *Tx {
 	return d.Begin()
 }
 
-func SetConfig(name, setting string) {
-	loadConfigs(nil)
-	conf := new(Config)
-	conf.ConfigureBy(setting)
-	dbConfigsLock.Lock()
-	dbConfigs[name] = conf
-	dbConfigsLock.Unlock()
-}
-
-func loadConfigs(logger *log.Logger) {
-	once.Do(func() {
-		if logger == nil {
-			logger = log.DefaultLogger
-		}
-		dbConfigs1 := make(map[string]*Config)
-		if err := config.Load(&dbConfigs1, "db"); err == nil {
-			for k, v := range dbConfigs1 {
-				if v.Host != "" {
-					dbConfigsLock.Lock()
-					dbConfigs[k] = v
-					dbConfigsLock.Unlock()
-				}
-			}
-		} else {
-			logger.Error(err.Error())
-		}
-		dbConfigs2 := make(map[string]string)
-		if err := config.Load(&dbConfigs2, "db"); err == nil {
-			for k, v := range dbConfigs2 {
-				if strings.Contains(v, "://") {
-					v2 := new(Config)
-					v2.ConfigureBy(v)
-					if v2.Host != "" {
-						v2.logger = logger
-						dbConfigsLock.Lock()
-						dbConfigs[k] = v2
-						dbConfigsLock.Unlock()
-					}
-				} else {
-					dbConfigsLock.Lock()
-					v2 := dbConfigs[v]
-					if v2 != nil && v2.Host != "" {
-						dbConfigs[k] = v2
-					}
-					dbConfigsLock.Unlock()
-				}
-			}
-		} else {
-			logger.Error(err.Error())
-		}
-	})
-}
-
 func getDB(name string, logger *log.Logger, useCache bool) *DB {
 	if logger == nil {
 		logger = log.DefaultLogger
@@ -485,7 +432,49 @@ func getDB(name string, logger *log.Logger, useCache bool) *DB {
 		conf.logger = logger
 		conf.ConfigureBy(name)
 	} else {
-		loadConfigs(logger)
+		dbConfigsLock.RLock()
+		n := len(dbConfigs)
+		dbConfigsLock.RUnlock()
+		if n == 0 {
+			once.Do(func() {
+				dbConfigs1 := make(map[string]*Config)
+				if err := config.Load(&dbConfigs1, "db"); err == nil {
+					for k, v := range dbConfigs1 {
+						if v.Host != "" {
+							dbConfigsLock.Lock()
+							dbConfigs[k] = v
+							dbConfigsLock.Unlock()
+						}
+					}
+				} else {
+					logger.Error(err.Error())
+				}
+				dbConfigs2 := make(map[string]string)
+				if err := config.Load(&dbConfigs2, "db"); err == nil {
+					for k, v := range dbConfigs2 {
+						if strings.Contains(v, "://") {
+							v2 := new(Config)
+							v2.ConfigureBy(v)
+							if v2.Host != "" {
+								v2.logger = logger
+								dbConfigsLock.Lock()
+								dbConfigs[k] = v2
+								dbConfigsLock.Unlock()
+							}
+						} else {
+							dbConfigsLock.Lock()
+							v2 := dbConfigs[v]
+							if v2 != nil && v2.Host != "" {
+								dbConfigs[k] = v2
+							}
+							dbConfigsLock.Unlock()
+						}
+					}
+				} else {
+					logger.Error(err.Error())
+				}
+			})
+		}
 		dbConfigsLock.RLock()
 		conf = dbConfigs[name]
 		dbConfigsLock.RUnlock()

README.md

@@ -22,10 +22,8 @@ go get apigo.cc/go/db
 ## 🛠 API 指南
 
 ### 1. 核心方法
-- **`SetConfig(name, setting string)`**
-  - 动态设置数据库配置（不依赖配置文件），可通过别名获取连接。
 - **`GetDB(name string, logger *log.Logger) *DB`**
-  - 获取数据库连接实例。`name` 可以是别名、`db.json` 中的配置名，也可以是标准 DSN（如 `mysql://user:pwd@host:port/db` 或 `sqlite://test.db`）。
+  - 获取数据库连接实例。`name` 可以是 `db.json` 中的配置名，也可以是标准 DSN（如 `mysql://user:pwd@host:port/db` 或 `sqlite://test.db`）。
 - **`Sync(schema string) error`**
   - 解析 DSL 并同步数据库表结构。用于创建表（包括 `_deleted` 表）和索引。详见 [架构 DSL 指南](./DSL.md)。
 

debug/debug_sync.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"fmt"
+	"apigo.cc/go/db"
+)
+
+func main() {
+	dbPath := "debug.db"
+	dbInst := db.GetDB("sqlite://"+dbPath, nil)
+	schema := `
+== System ==
+_Table SD
+  id c10 PK
+  name v64 U
+`
+	fmt.Println("First sync...")
+	dbInst.Sync(schema)
+
+	fmt.Println("\nSecond sync...")
+	dbInst.Sync(schema)
+}

debug/go.mod

@@ -0,0 +1,3 @@
+module debug
+
+go 1.26.1

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/go-sql-driver/mysql v1.10.0
 	github.com/jackc/pgx/v5 v5.9.2
 	github.com/mitchellh/mapstructure v1.5.0
-	modernc.org/sqlite v1.51.0
+	modernc.org/sqlite v1.50.0
 )
 
 require (
@@ -29,7 +29,7 @@ require (
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
-	github.com/mattn/go-isatty v0.0.22 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	golang.org/x/crypto v0.52.0 // indirect
@@ -37,7 +37,7 @@ require (
 	golang.org/x/sys v0.45.0 // indirect
 	golang.org/x/text v0.37.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	modernc.org/libc v1.72.5 // indirect
+	modernc.org/libc v1.72.0 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect
 )

go.sum

@@ -51,7 +51,8 @@ github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
 github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/mattn/go-isatty v0.0.22 h1:j8l17JJ9i6VGPUFUYoTUKPSgKe/83EYU2zBC7YNKMw4=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
 github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
@@ -73,6 +74,7 @@ golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
 golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=
 golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
 golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.45.0 h1:dO4czNzziLiiXplLQgBCEpCvXQ3dnkn0SdaZSYdQ+FY=
 golang.org/x/sys v0.45.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
 golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
@@ -85,24 +87,30 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EV
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-modernc.org/cc/v4 v4.28.2 h1:3tQ0lf2ADtoby2EtSP+J7IE2SHwEJdP8ioR59wx7XpY=
+modernc.org/cc/v4 v4.27.3 h1:uNCgn37E5U09mTv1XgskEVUJ8ADKpmFMPxzGJ0TSo+U=
-modernc.org/ccgo/v4 v4.34.2 h1:mxsy2FdrB6+qG3NfXefz1AmWv0ehOSDO4jxgxd7h9yo=
+modernc.org/cc/v4 v4.27.3/go.mod h1:3YjcbCqhoTTHPycJDRl2WZKKFj0nwcOIPBfEZK0Hdk8=
+modernc.org/ccgo/v4 v4.32.4 h1:L5OB8rpEX4ZsXEQwGozRfJyJSFHbbNVOoQ59DU9/KuU=
+modernc.org/ccgo/v4 v4.32.4/go.mod h1:lY7f+fiTDHfcv6YlRgSkxYfhs+UvOEEzj49jAn2TOx0=
 modernc.org/fileutil v1.4.0 h1:j6ZzNTftVS054gi281TyLjHPp6CPHr2KCxEXjEbD6SM=
 modernc.org/fileutil v1.4.0/go.mod h1:EqdKFDxiByqxLk8ozOxObDSfcVOv/54xDs/DUHdvCUU=
 modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
 modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
-modernc.org/gc/v3 v3.1.3 h1:6QAplYyVO+KdPW3pGnqmJDUxtkec8ooEWvks/hhU3lc=
+modernc.org/gc/v3 v3.1.2 h1:ZtDCnhonXSZexk/AYsegNRV1lJGgaNZJuKjJSWKyEqo=
+modernc.org/gc/v3 v3.1.2/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
 modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
 modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
-modernc.org/libc v1.72.5 h1:m2OGx9Ser1VvTS4Z9ZJlWs+CBMxutLaTiAWkNz+NB9U=
+modernc.org/libc v1.72.0 h1:IEu559v9a0XWjw0DPoVKtXpO2qt5NVLAnFaBbjq+n8c=
+modernc.org/libc v1.72.0/go.mod h1:tTU8DL8A+XLVkEY3x5E/tO7s2Q/q42EtnNWda/L5QhQ=
 modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
 modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
 modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
 modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
-modernc.org/opt v0.2.0 h1:tGyef5ApycA7FSEOMraay9SaTk5zmbx7Tu+cJs4QKZg=
+modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
+modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
 modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
 modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
-modernc.org/sqlite v1.51.0 h1:aH/MMSoayAIhozZ7uJbVTT9QO/VhzBf0J9tymmmuC/U=
+modernc.org/sqlite v1.50.0 h1:eMowQSWLK0MeiQTdmz3lqoF5dqclujdlIKeJA11+7oM=
+modernc.org/sqlite v1.50.0/go.mod h1:m0w8xhwYUVY3H6pSDwc3gkJ/irZT/0YEXwBlhaxQEew=
 modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
 modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
 modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=

js_export.go

@@ -12,106 +12,48 @@ import (
 
 func init() {
 	jsmod.Register("db", map[string]any{
-		// 入口：支持别名获取，不传则默认 "default"
+		"get": func(ctx context.Context, name string) (*jsDB, error) {
-		"Get": func(ctx context.Context, name *string) (*jsDB, error) {
+			isReadOnly := false
-			target := "default"
-			if name != nil {
-				target = *name
-			}
-			return getJSDB(ctx, target)
-		},
 
-		// 默认快捷调用 (面向 "default" 实例)
+			// 安全模式下的动态判定
-		"Query": func(ctx context.Context, query string, args ...any) (*QueryResult, error) {
+			if jsmod.IsSafeMode(ctx) {
-			jd, err := getJSDB(ctx, "default")
+				if strings.HasPrefix(name, "sqlite://") {
-			if err != nil {
+					// 1. SQLite 路径校验
-				return nil, err
+					path := strings.TrimPrefix(name, "sqlite://")
-			}
+					if idx := strings.Index(path, "?"); idx != -1 {
-			return jd.Query(query, args...), nil
+						path = path[:idx]
-		},
+					}
-		"Exec": func(ctx context.Context, query string, args ...any) (*ExecResult, error) {
+					// 如果路径不在沙箱内，VerifyPathForSafeMode 会直接返回 error，阻止连接
-			jd, err := getJSDB(ctx, "default")
+					_, err := file.VerifyPathForSafeMode(ctx, path)
-			if err != nil {
+					if err != nil {
-				return nil, err
+						return nil, err
-			}
+					}
-			return jd.Exec(query, args...), nil
+					isReadOnly = false
-		},
+				} else {
-		"Insert": func(ctx context.Context, table string, data any) (*ExecResult, error) {
+					// 2. 远程数据库前缀校验
-			jd, err := getJSDB(ctx, "default")
+					var allowedDSNs []string
-			if err != nil {
+					cast.Convert(&allowedDSNs, ctx.Value("AllowedDSNs"))
-				return nil, err
+					matched := false
-			}
+					for _, prefix := range allowedDSNs {
-			return jd.Insert(table, data), nil
+						if strings.HasPrefix(name, prefix) {
-		},
+							matched = true
-		"Update": func(ctx context.Context, table string, data any, conditions string, args ...any) (*ExecResult, error) {
+							break
-			jd, err := getJSDB(ctx, "default")
+						}
-			if err != nil {
+					}
-				return nil, err
+					if !matched {
-			}
+						// 未命中白名单，降级为只读模式
-			return jd.Update(table, data, conditions, args...), nil
+						isReadOnly = true
-		},
+					}
-		"Delete": func(ctx context.Context, table string, conditions string, args ...any) (*ExecResult, error) {
-			jd, err := getJSDB(ctx, "default")
-			if err != nil {
-				return nil, err
-			}
-			return jd.Delete(table, conditions, args...), nil
-		},
-		"Replace": func(ctx context.Context, table string, data any) (*ExecResult, error) {
-			jd, err := getJSDB(ctx, "default")
-			if err != nil {
-				return nil, err
-			}
-			return jd.Replace(table, data), nil
-		},
-		"Begin": func(ctx context.Context) (*jsTx, error) {
-			jd, err := getJSDB(ctx, "default")
-			if err != nil {
-				return nil, err
-			}
-			return jd.Begin()
-		},
-	})
-}
-
-func getJSDB(ctx context.Context, name string) (*jsDB, error) {
-	isReadOnly := false
-
-	// 安全模式下的动态判定
-	if jsmod.IsSafeMode(ctx) {
-		if strings.HasPrefix(name, "sqlite://") {
-			// 1. SQLite 路径校验
-			path := strings.TrimPrefix(name, "sqlite://")
-			if idx := strings.Index(path, "?"); idx != -1 {
-				path = path[:idx]
-			}
-			_, err := file.VerifyPathForSafeMode(ctx, path)
-			if err != nil {
-				return nil, err
-			}
-			isReadOnly = false
-		} else {
-			// 2. 远程数据库前缀校验
-			var allowedDSNs []string
-			cast.Convert(&allowedDSNs, jsmod.Get(ctx, "AllowedDSNs"))
-			matched := false
-			for _, prefix := range allowedDSNs {
-				if strings.HasPrefix(name, prefix) {
-					matched = true
-					break
 				}
 			}
-			if !matched {
-				isReadOnly = true
-			}
-		}
-	}
 
-	d := GetDB(name, nil)
+			d := GetDB(name, nil)
-	if d.Error != nil {
+			if d.Error != nil {
-		return nil, d.Error
+				return nil, d.Error
-	}
+			}
-	return &jsDB{db: d, ctx: ctx, isReadOnly: isReadOnly}, nil
+			return &jsDB{db: d, ctx: ctx, isReadOnly: isReadOnly}, nil
+		},
+	})
 }
 
 type jsDB struct {
@@ -179,10 +121,6 @@ func (jd *jsDB) Begin() (*jsTx, error) {
 	return &jsTx{tx: tx, ctx: jd.ctx, isReadOnly: jd.isReadOnly}, nil
 }
 
-// Metadata
-func (jd *jsDB) InKeys(numArgs int) string { return jd.db.InKeys(numArgs) }
-func (jd *jsDB) Quote(text string) string  { return jd.db.Quote(text) }
-
 // jsTx wraps *Tx for JS environment
 type jsTx struct {
 	tx         *Tx
@@ -244,3 +182,7 @@ func (jt *jsTx) Commit() error {
 }
 
 func (jt *jsTx) Rollback() error { return jt.tx.Rollback() }
+
+// Metadata
+func (jd *jsDB) InKeys(numArgs int) string { return jd.db.InKeys(numArgs) }
+func (jd *jsDB) Quote(text string) string  { return jd.db.Quote(text) }

test_idx.sh

@@ -0,0 +1,5 @@
+rm -f test_idx.db
+sqlite3 test_idx.db "CREATE TABLE test (name TEXT);"
+sqlite3 test_idx.db "CREATE INDEX idx_name ON test(name);"
+sqlite3 test_idx.db "CREATE UNIQUE INDEX IF NOT EXISTS idx_name ON test(name);"
+echo "Result code: $?"

test_unique.sh

@@ -0,0 +1,6 @@
+rm -f test_unique.db
+sqlite3 test_unique.db "CREATE TABLE test (name TEXT);"
+sqlite3 test_unique.db "INSERT INTO test (name) VALUES ('a');"
+sqlite3 test_unique.db "INSERT INTO test (name) VALUES ('b');"
+sqlite3 test_unique.db "CREATE UNIQUE INDEX uk_test_name ON test(name);"
+echo "Result code: $?"

test_unique_dup.sh

@@ -0,0 +1,6 @@
+rm -f test_unique.db
+sqlite3 test_unique.db "CREATE TABLE test (name TEXT);"
+sqlite3 test_unique.db "INSERT INTO test (name) VALUES ('a');"
+sqlite3 test_unique.db "INSERT INTO test (name) VALUES ('a');"
+sqlite3 test_unique.db "CREATE UNIQUE INDEX uk_test_name ON test(name);"
+echo "Result code: $?"

unique_race_test.go

@@ -0,0 +1,46 @@
+package db
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+func TestCheckTable_DuplicateUnique(t *testing.T) {
+	dbPath := "test_unique_race.db"
+	_ = os.Remove(dbPath)
+	defer os.Remove(dbPath)
+
+	dbInst := GetDB("sqlite://"+dbPath, nil)
+	
+	schema := `
+== System ==
+_Table SD
+  id c10 PK
+  name v64 U
+`
+    // First sync
+	err := dbInst.Sync(schema)
+	if err != nil {
+		t.Fatalf("First sync failed: %v", err)
+	}
+
+	// Insert duplicates to ensure recreation fails
+	dbInst.Exec("INSERT INTO _Table (id, name) VALUES ('1', 'dup')")
+	dbInst.Exec("INSERT INTO _Table (id, name) VALUES ('2', 'dup')") // Will fail if unique constraint works, but wait, the unique index is already there, so we can't insert duplicates! 
+	// Wait, we CAN'T insert duplicates because the first sync created the index.
+	// But in the user's log, there ARE duplicates? Or maybe there are NO duplicates, but the engine just complains when it recreates the index on existing data?
+	// Ah, if there are NO duplicates, CREATE UNIQUE INDEX will SUCCEED.
+	// So why did the user get UNIQUE constraint failed? 
+	// BECAUSE THERE WERE DUPLICATES!
+	// Why would there be duplicates in _Table?
+	// Let's just do the second sync and see if it tries to execute CREATE UNIQUE INDEX.
+	
+	// Print statements will be inside Schema.go for a moment.
+	
+    // Second sync (simulate restart)
+    err = dbInst.Sync(schema)
+	if err != nil {
+		t.Fatalf("Second sync failed: %v", err)
+	}
+}