增加pagehelper扩展性，增加数据库支持

xfali · xfali · commit 2bd6e642f85c · 2020-01-19T21:13:34.000+08:00
diff --git a/modifier.go b/modifier.go
@@ -0,0 +1,38 @@
+// Copyright (C) 2019-2020, Xiongfa Li.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+const (
+    DriverDummy     = "default"
+    DriverMysql     = "mysql"
+    DriverPostgre   = "postgre"
+    DriverOracle    = "oracle"
+    DriverSqlServer = "sqlserver"
+)
+
+type Modifier struct {
+    OrderBy func(sql string, p *OrderByInfo) string
+    Page    func(sql string, p *PageInfo) string
+    Count   func(sql, countColumn string) string
+}
+
+var DummyModifier = Modifier{
+    OrderBy: DummyModifyOrderBy,
+    Page:    DummyModifyPage,
+    Count:   DummyModifyCount,
+}
+
+func DummyModifyOrderBy(sql string, p *OrderByInfo) string {
+    return sql
+}
+
+func DummyModifyPage(sql string, p *PageInfo) string {
+    return sql
+}
+
+func DummyModifyCount(sql, countColumn string) string {
+    return sql
+}
diff --git a/modifier_mysql.go b/modifier_mysql.go
@@ -0,0 +1,49 @@
+// Copyright (C) 2019-2020, Xiongfa Li.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+import (
+    "fmt"
+    "strings"
+)
+
+var MysqlModifier = Modifier{
+    OrderBy: MysqlModifyOrderBy,
+    Page:    MysqlModifyPage,
+    Count:   MysqlModifyCount,
+}
+
+func MysqlModifyOrderBy(sql string, p *OrderByInfo) string {
+    if p.Field == "" {
+        return sql
+    }
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
+    return b.String()
+}
+
+func MysqlModifyPage(sql string, p *PageInfo) string {
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" LIMIT %d, %d ", p.Page*p.PageSize, p.PageSize))
+    return b.String()
+}
+
+func MysqlModifyCount(sql, countColumn string) string {
+    if countColumn == "" {
+        countColumn = "0"
+    } else {
+        countColumn = "`" + countColumn + "`"
+    }
+    b := strings.Builder{}
+    b.WriteString("SELECT COUNT(")
+    b.WriteString(countColumn)
+    b.WriteString(") FROM (")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(") AS __hp_tempCountTl")
+    return b.String()
+}
diff --git a/modifier_oracle.go b/modifier_oracle.go
@@ -0,0 +1,52 @@
+// Copyright (C) 2019-2020, Xiongfa Li.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+import (
+    "fmt"
+    "strings"
+)
+
+var OracleModifier = Modifier{
+    OrderBy: OracleModifyOrderBy,
+    Page:    OracleModifyPage,
+    Count:   OracleModifyCount,
+}
+
+func OracleModifyOrderBy(sql string, p *OrderByInfo) string {
+    if p.Field == "" {
+        return sql
+    }
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
+    return b.String()
+}
+
+func OracleModifyPage(sql string, p *PageInfo) string {
+    b := strings.Builder{}
+    b.WriteString("SELECT * FROM ( ")
+    b.WriteString(" SELECT __hp_tempPageTl.*, ROWNUM ROW_ID FROM ( ")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(" ) __hp_tempPageTl)")
+    b.WriteString(fmt.Sprintf(" WHERE ROW_ID <= %d AND ROW_ID > %d ", p.Page*p.PageSize, p.PageSize))
+    return b.String()
+}
+
+func OracleModifyCount(sql, countColumn string) string {
+    if countColumn == "" {
+        countColumn = "0"
+    } else {
+        countColumn = "`" + countColumn + "`"
+    }
+    b := strings.Builder{}
+    b.WriteString("SELECT COUNT(")
+    b.WriteString(countColumn)
+    b.WriteString(") FROM (")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(") AS __hp_tempCountTl")
+    return b.String()
+}
diff --git a/modifier_postgre.go b/modifier_postgre.go
@@ -0,0 +1,49 @@
+// Copyright (C) 2019-2020, Xiongfa Li.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+import (
+    "fmt"
+    "strings"
+)
+
+var PostgreModifier = Modifier{
+    OrderBy: PostgreModifyOrderBy,
+    Page:    PostgreModifyPage,
+    Count:   PostgreModifyCount,
+}
+
+func PostgreModifyOrderBy(sql string, p *OrderByInfo) string {
+    if p.Field == "" {
+        return sql
+    }
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
+    return b.String()
+}
+
+func PostgreModifyPage(sql string, p *PageInfo) string {
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" OFFSET %d LIMIT %d ", p.Page*p.PageSize, p.PageSize))
+    return b.String()
+}
+
+func PostgreModifyCount(sql, countColumn string) string {
+    if countColumn == "" {
+        countColumn = "0"
+    } else {
+        countColumn = "`" + countColumn + "`"
+    }
+    b := strings.Builder{}
+    b.WriteString("SELECT COUNT(")
+    b.WriteString(countColumn)
+    b.WriteString(") FROM (")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(") AS __hp_tempCountTl")
+    return b.String()
+}
diff --git a/modifier_sqlserver.go b/modifier_sqlserver.go
@@ -0,0 +1,49 @@
+// Copyright (C) 2019-2020, Xiongfa Li.
+// @author xiongfa.li
+// @version V1.0
+// Description: 
+
+package pagehelper
+
+import (
+    "fmt"
+    "strings"
+)
+
+var SqlServerModifier = Modifier{
+    OrderBy: SqlServerModifyOrderBy,
+    Page:    SqlServerModifyPage,
+    Count:   SqlServerModifyCount,
+}
+
+func SqlServerModifyOrderBy(sql string, p *OrderByInfo) string {
+    if p.Field == "" {
+        return sql
+    }
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
+    return b.String()
+}
+
+func SqlServerModifyPage(sql string, p *PageInfo) string {
+    b := strings.Builder{}
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(fmt.Sprintf(" OFFSET %d ROWS FETCH NEXT %d ROWS ONLY ", p.Page*p.PageSize, p.PageSize))
+    return b.String()
+}
+
+func SqlServerModifyCount(sql, countColumn string) string {
+    if countColumn == "" {
+        countColumn = "0"
+    } else {
+        countColumn = "`" + countColumn + "`"
+    }
+    b := strings.Builder{}
+    b.WriteString("SELECT COUNT(")
+    b.WriteString(countColumn)
+    b.WriteString(") FROM (")
+    b.WriteString(strings.TrimSpace(sql))
+    b.WriteString(") AS __hp_tempCountTl")
+    return b.String()
+}
diff --git a/orm.go b/orm.go
@@ -17,7 +17,6 @@ import (
     "github.com/xfali/gobatis/reflection"
     "github.com/xfali/gobatis/session"
     "github.com/xfali/gobatis/transaction"
-    "strings"
 )
 
 const (
@@ -28,19 +27,15 @@ const (
     DESC = "DESC"
 )
 
-var (
-    OrderByModifier = modifyOrderSql
-    PageModifier    = modifyPageSql
-    CountModifier   = modifyCountSql
-)
-
 type Factory struct {
     fac factory.Factory
 }
 
 type Executor struct {
     exec executor.Executor
     log  logging.LogFunc
+
+    modifier Modifier
 }
 
 func New(f factory.Factory) *Factory {
@@ -72,14 +67,14 @@ func (exec *Executor) Query(ctx context.Context, result reflection.Object, sql s
     o := ctx.Value(orderHelperValue)
     if o != nil {
         if param, ok := o.(*OrderByInfo); ok {
-            sql = OrderByModifier(sql, param)
+            sql = exec.modifier.OrderBy(sql, param)
         }
     }
 
     p := ctx.Value(pageHelperValue)
     if p != nil {
         if param, ok := p.(*PageInfo); ok {
-            sql = PageModifier(sql, param)
+            sql = exec.modifier.Page(sql, param)
             if param.total == -1 {
                 param.total = exec.getTotal(ctx, originSql, param.countColumn, params...)
             }
@@ -111,31 +106,20 @@ func (f *Factory) LogFunc() logging.LogFunc {
 }
 
 func (f *Factory) CreateExecutor(transaction transaction.Transaction) executor.Executor {
-    return &Executor{
-        exec: executor.NewSimpleExecutor(transaction),
-        log:  f.LogFunc(),
+    driver := ""
+    if defaultFac, ok := f.fac.(*factory.DefaultFactory); ok {
+        driver = defaultFac.DataSource.DriverName()
     }
-}
 
-func modifyOrderSql(sql string, p *OrderByInfo) string {
-    if p.Field == "" {
-        return sql
+    return &Executor{
+        exec:     executor.NewSimpleExecutor(transaction),
+        log:      f.LogFunc(),
+        modifier: SelectModifier(driver),
     }
-    b := strings.Builder{}
-    b.WriteString(strings.TrimSpace(sql))
-    b.WriteString(fmt.Sprintf(" ORDER BY `%s` %s ", p.Field, p.Order))
-    return b.String()
-}
-
-func modifyPageSql(sql string, p *PageInfo) string {
-    b := strings.Builder{}
-    b.WriteString(strings.TrimSpace(sql))
-    b.WriteString(fmt.Sprintf(" LIMIT %d, %d ", p.Page*p.PageSize, p.PageSize))
-    return b.String()
 }
 
 func (exec *Executor) getTotal(ctx context.Context, sql, countColumn string, params ...interface{}) int64 {
-    totalSql := CountModifier(sql, countColumn)
+    totalSql := exec.modifier.Count(sql, countColumn)
     var total int64
     obj, err := gobatis.ParseObject(&total)
     if err == nil {
@@ -145,17 +129,23 @@ func (exec *Executor) getTotal(ctx context.Context, sql, countColumn string, par
     return 0
 }
 
-func modifyCountSql(sql, countColumn string) string {
-    if countColumn == "" {
-        countColumn = "0"
-    } else {
-        countColumn = "`" + countColumn + "`"
+var modifierMap = map[string]Modifier{
+    DriverDummy:     DummyModifier,
+    DriverMysql:     MysqlModifier,
+    DriverOracle:    OracleModifier,
+    DriverPostgre:   PostgreModifier,
+    DriverSqlServer: SqlServerModifier,
+}
+
+func RegisterModifier(driver string, m Modifier) {
+    if driver != "" {
+        modifierMap[driver] = m
+    }
+}
+
+func SelectModifier(driver string) Modifier {
+    if m, ok := modifierMap[driver]; ok {
+        return m
     }
-    b := strings.Builder{}
-    b.WriteString("SELECT COUNT(")
-    b.WriteString(countColumn)
-    b.WriteString(") FROM (")
-    b.WriteString(strings.TrimSpace(sql))
-    b.WriteString(") AS __hp_tempCountTl")
-    return b.String()
+    return modifierMap[DriverDummy]
 }
diff --git a/pagehelper_test.go b/pagehelper_test.go
