# CsvDb ʹÓÃÊÖ²á ±¾Îĵµ»ùÓÚÔ´Âë `NewLife.Core/IO/CsvDb.cs` ÓëÆäÒÀÀµ `NewLife.Core/IO/CsvFile.cs`£¬ÓÃÓÚ˵Ã÷ `CsvDb<T>`£¨CSV ÎļþÇáÁ¿¼¶Êý¾Ý¿â£©µÄÉè¼ÆÄ¿±ê¡¢Êý¾Ý¸ñʽ¡¢ÊÂÎñÄ£ÐÍÓë CRUD Ó÷¨¡£ > ¹Ø¼ü´Ê£º×·¼Óд¡¢¸ßÐÔÄÜ˳Ðò²éѯ¡¢Ìø¹ýËð»µÐС¢±íÍ·Ó³Éä¡¢ÊÂÎñ»º´æ¡¢·´É仺´æ¡¢ÐòÁл¯ÊôÐÔÃû¡£ --- ## 1. ¸ÅÊö `CsvDb<T>` ÊÇÒ»¸öÒÔ CSV Îļþ×÷Ϊ³Ö¾Ã»¯´æ´¢µÄ¡°ÇáÁ¿¼¶Êý¾Ý¿â¡±£¬Êʺϣº - ´óÁ¿Êý¾ÝÐèÒª **¿ìËÙ×·¼Ó£¨Append£©**£» - ÐèÒª **˳ÐòɨÃèʽ¿ìËÙ²éѯ**£¨`Query`£©£» - ºÜÉÙÐÞ¸Ä/ɾ³ý£¨ÐÞ¸Ä/ɾ³ý±¾ÖÊÊÇ¡°È«Á¿ÖØд¡±£©£» - ×ÀÃæ¶Ë³¡¾°£¬SQLite µÈ¹Øϵ¿â¿ÉÄÜÒò·Ç·¨¹Ø»úµ¼ÖÂË𻵣»`CsvDb<T>` ¶Áȡʱ¿É **Ìø¹ýËð»µÐÐ**£¬Ìá¸ß¿É»Ö¸´ÐÔ¡£ ÖØÒªÔ¼Êø£º - **²»Ö§³ÖḬ̈߳²È«**£ºÀà×¢ÊÍÃ÷È·ÒªÇó¡°Îñ±ØÈ·±£µ¥Ï̲߳Ù×÷¡±¡£Ô´ÂëÖв¿·Ö·½·¨Ê¹Óà `lock (this)` ·À²¢·¢£¬µ«²¢·ÇÍêÕû²¢·¢Éè¼Æ¡£ --- ## 2. Êý¾ÝÎļþ¸ñʽ ### 2.1 ÎļþÍ·£¨Header£© Ê×ÐÐÊÇÁÐÃû£¬À´Ô´ÓÚʵÌå `T` µÄ¹«¹²ÊµÀýÊôÐÔ£º - ͨ¹ý·´É仺´æ `_properties = typeof(T).GetProperties(...)` »ñÈ¡ÊôÐÔ£» - ÁÐÃûʹÓà `SerialHelper.GetName(PropertyInfo)`£¨¶ø²»ÊÇÊôÐÔÃû£©£¬ÒÔ±£³ÖÓëÐòÁл¯Ãû/ÌØÐÔÒ»Ö¡£ дÎļþʱ£º - µ±ÎļþΪ¿Õ£¨`FileStream.Position == 0`£©Ê±Ð´Èë±íÍ·¡£ ¶ÁÈ¡Îļþʱ£º - Ê×ÐÐ×÷Ϊ CSV ÁÐÃû£» - ½¨Á¢¡°ÎļþÁÐ -> ÊôÐÔË÷Òý¡±µÄÓ³ÉäÊý×é `columnToProperty`£¬±ÜÃâÿÐж¼²é×ֵ䡣 ### 2.2 Êý¾ÝÐУ¨Data Rows£© ÿÐжÔÓ¦Ò»¸ö `T` ʵÀý¡£ дÈëʱ£º - Èô `T` ʵÏÖ `IModel`£º°´ÊôÐÔÃû `src[e.Name]` ¶ÁÈ¡Öµ£» - ·ñÔòͨ¹ý·´Éä `item.GetValue(e)` ¶ÁÈ¡ÊôÐÔÖµ¡£ ¶Áȡʱ£º - ´´½¨ `new T()`£» - ¶ÔÿÁг¢ÊÔ°´Ä¿±êÊôÐÔÀàÐÍ×ö»ù´¡Ð£Ñ飨ÕûÊý/¸¡µã/ÈÕÆڵȣ©£¬Ð£Ñéʧ°ÜÔòÌø¹ý¸Ã×ֶΣ» - ½«×Ö·û´® `raw` ת»»ÎªÄ¿±êÀàÐÍ£º`raw.ChangeType(pi.PropertyType)`£» - ÔÙͨ¹ý `IModel` »ò `model.SetValue(pi, value)` ¸³Öµ¡£ --- ## 3. ºËÐÄÊôÐÔ ### 3.1 `FileName` - ÀàÐÍ£º`String?` - ÓïÒ壺CSV Êý¾ÝÎļþ·¾¶ ʹÓÃÒªÇó£º - ±ØÐëÉèÖã»Î´ÉèÖõ÷ÓûáÅ׳ö `ArgumentNullException`£¨¼û `GetFile()`£©¡£ ### 3.2 `Encoding` - ÀàÐÍ£º`Encoding` - ĬÈÏ£º`Encoding.UTF8` Ó°Ï죺 - ¶ÁÈ¡ÓëдÈë CSV ʱ´«µÝ¸ø `CsvFile.Encoding`¡£ ### 3.3 `Comparer` - ÀàÐÍ£º`IEqualityComparer<T>` - ĬÈÏ£º`EqualityComparer<T>.Default` ÓÃ;£º - `Remove(T)` / `Remove(IEnumerable<T>)` / `Find(T)` / `Set(T, ...)` ÓÃËüÀ´Åжϡ°ÊµÌåÊÇ·ñÏàͬ¡±¡£ ¿Éͨ¹ý¹¹Ô캯Êý `CsvDb(Func<T?, T?, Boolean> comparer)` ´«Èë×Ô¶¨Òå±È½ÏÂß¼­¡£ --- ## 4. ÊÂÎñÄ£ÐÍ£¨»º´æд£© ### 4.1 `BeginTransaction()` - ÐÐΪ£º°Ñµ±Ç°ÎļþÈ«²¿Êý¾Ý¶ÁÈëÄڴ棨`_cache = FindAll().ToList()`£©¡£ - Ö®ºóµÄ `Add/Remove/Set/Clear/Find/Query` ½«»ùÓÚ»º´æ²Ù×÷£¨±ÜÃâƵ·± I/O£©¡£ ### 4.2 `Commit()` - ÐÐΪ£º°Ñ `_cache` ¸²¸Çд»ØÎļþ£¨`Write(_cache, false)`£©£¬È»ºóÇå¿Õ»º´æ¡£ ### 4.3 `Rollback()` - ÐÐΪ£º½öÇå¿Õ»º´æ£¬²»Ð´»Ø´ÅÅÌ¡£ ### 4.4 Dispose ×Ô¶¯Ìá½» `CsvDb<T>` ¼Ì³Ð `DisposeBase`£¬Æä `Dispose(Boolean)` ¸²¸ÇÖлáµ÷Óà `Commit()`£º - Èô¿ªÆô¹ýÊÂÎñÇÒÈÔÓлº´æ£¬ÊͷŶÔÏóʱ»á×Ô¶¯Ìá½»£¨±£³ÖÀúÊ·¼æÈÝÐÐΪ£©¡£ ½¨Ò飺 - ¶Ô¡°Åú´¦Àí¡±ÎªÖ÷µÄ³¡¾°£¬½¨ÒéÏÔʾµ÷Óà `Commit()`£¬±ÜÃâÒ쳣ʱÎóÌá½»¡£ --- ## 5. дÈë/×·¼Ó ### 5.1 `Write(IEnumerable<T> models, Boolean append)` ÓïÒ壺ÅúÁ¿Ð´Èë¡£ ¹Ø¼üµã£º - ´ò¿ªÎļþ·½Ê½£º`FileMode.OpenOrCreate` + `FileAccess.ReadWrite` + `FileShare.ReadWrite`£» - `append=true` ʱÒƶ¯µ½Îļþβ£º`fs.Position = fs.Length`£» - ÎļþΪ¿ÕʱдÈë±íÍ·£» - дÍêºóÖ´ÐÐ `fs.SetLength(fs.Position)`£º - ¸²¸Çд£¨`append=false`£©³¡¾°£º½Ø¶ÏÔ­Îļþ¶àÓಿ·Ö£» - ×·¼ÓдʱҲ»á°Ñ³¤¶ÈÉèÖÃΪµ±Ç°Î»Öã¨Í¨³£µÈ¼Û£©¡£ ### 5.2 `Add(T model)` / `Add(IEnumerable<T> models)` - ÈôÒÑ `BeginTransaction()`£º½ö×·¼Óµ½ `_cache`£» - ·ñÔò£ºÖ±½Ó `Write(..., append:true)`£¬ÐÔÄÜ×îºÃ¡£ --- ## 6. ²éѯ ### 6.1 `IEnumerable<T> Query(Func<T, Boolean>? predicate, Int32 count = -1)` ÓïÒ壺˳ÐòɨÃè²éѯ£¬°´Ðè·µ»Ø¡£ ÐÐΪҪµã£º - ¿ªÆôÊÂÎñ£¨`_cache!=null`£©Ê±£º´Ó»º´æö¾Ù£¬ÃüÖÐÔò `yield return`£» - 먦ÆôÊÂÎñʱ£º - ʹÓà `CsvFile.ReadLine()` Öð¼Ç¼¶ÁÈ¡£» - Ê×Ìõ¼Ç¼×÷Ϊ±íÍ·£» - ºóÐøÿÌõ¼Ç¼¸ù¾ÝÓ³ÉäÌî³äµ½Ð¶ÔÏó¡£ Ëð»µÐд¦Àí£º - ÀàÐÍת»»¹ý³ÌÖÐÈκÎÒì³£»á±»²¶»ñ²¢¼Ç¼£¨`XTrace.WriteException(ex)`£©£¬¸ÃÐÐÌø¹ý£» - ÈôÒ»ÐÐÖÐûÓÐÈκÎ×ֶγɹ¦Æ¥Å䣨`success == 0`£©£¬ÊÓΪËð»µÐв¢Ìø¹ý¡£ `count`£º - ĬÈÏ `-1` ±íʾ²»ÏÞÖÆ£» - ÿ `yield` Ò»´Îºó `--count`£¬µ½ 0 ½áÊø¡£ ### 6.2 `T? Find(Func<T, Boolean>? predicate)` - µÈ¼ÛÓÚ `Query(predicate, 1).FirstOrDefault()`¡£ ### 6.3 `IList<T> FindAll()` - ¿ªÆôÊÂÎñʱ·µ»Ø»º´æ¸±±¾ `_cache.ToList()`£» - ·ñÔò¶ÁÈ¡È«²¿¡£ ### 6.4 `Int32 FindCount()` - ·ÇÊÂÎñ³¡¾°£ºÊ¹Óà `StreamReader.ReadLine()` ÖðÐмÆÊý£¨Ìø¹ýÍ·²¿£©¡£ - ×¢Ò⣺ÕâÀï°´ÎïÀíÐмÆÊý£¬²»¿¼ÂÇ CSV ÒýºÅ×Ö¶ÎÄÚ»»ÐеÄÇé¿ö£»ÔÚ³£¹æ±í¸ñÐÍ CSV ÖÐͨ³£¿É½ÓÊÜ¡£ --- ## 7. ¸üÐÂÓëɾ³ý£¨È«Á¿ÖØд£¬½ÏÂý£© ### 7.1 `Remove(Func<T, Boolean> predicate)` - Èô¿ªÆôÊÂÎñ£º¶Ô `_cache` Ö´ÐÐ `RemoveAll`£» - ·ñÔò£º - `FindAll()` ¶ÁÈëÈ«²¿£» - ¹ýÂ˵ôÃüÖÐÏ - ÔÙ `Write(list, false)` ¸²¸Çд»Ø¡£ ### 7.2 `Update(T model)` / `Set(T model)` - `Update`£ºÖ»¸üУ¬²»´æÔÚÔò·µ»Ø `false`£» - `Set`£º´æÔÚÔò¸üУ¬²»´æÔÚÔò×·¼ÓÒ»Ìõ¡£ 먦ÆôÊÂÎñʱ£º - ¶ÁÈ¡È«²¿µ½Äڴ棬Ð޸ĺ󸲸Çд»Ø¡£ --- ## 8. Òì²½²éѯ£¨net5+ / netstandard2.1+£© ÔÚ `NET5_0_OR_GREATER || NETSTANDARD2_1_OR_GREATER` ÏÂÌṩ£º - `IAsyncEnumerable<T> QueryAsync(Func<T, Boolean>? predicate, Int32 count = -1)` - `Task<IList<T>> FindAllAsync()` ʵÏÖÒªµã£º - ÄÚ²¿Ê¹Óà `CsvFile.ReadAllAsync()`£» - Í·²¿Ó³ÉäÂß¼­Óëͬ²½°æÒ»Ö£» - ·¢ÉúÒ쳣ʱͬÑù¼Ç¼²¢Ìø¹ýÐС£ --- ## 9. ×îСʾÀý ### 9.1 ¶¨ÒåʵÌå ```csharp public class User { public Int32 Id { get; set; } public String? Name { get; set; } public DateTime CreateTime { get; set; } } ``` ### 9.2 ×·¼ÓдÈë ```csharp using NewLife.IO; var db = new CsvDb<User> { FileName = "./user.csv", Encoding = Encoding.UTF8, }; db.Add(new User { Id = 1, Name = "Stone", CreateTime = DateTime.Now }); db.Add(new User { Id = 2, Name = "NewLife", CreateTime = DateTime.Now }); ``` ### 9.3 ²éѯ ```csharp foreach (var u in db.Query(e => e.Id > 0)) { Console.WriteLine($"{u.Id} {u.Name}"); } ``` ### 9.4 Åú´¦ÀíÊÂÎñ ```csharp using var db = new CsvDb<User> { FileName = "./user.csv" }; db.BeginTransaction(); db.Add(new User { Id = 3, Name = "Tx" }); db.Remove(e => e.Id == 1); db.Commit(); ``` --- ## 10. ×¢ÒâÊÂÏîÓë×î¼Ñʵ¼ù 1. **¸ßƵдÈëÓÅÏÈÓà `Add`£¨·ÇÊÂÎñ£©**£ºËü×ß×·¼Óд·¾¶£¬±ÜÃâÈ«Á¿ÖØд¡£ 2. **ÐÞ¸Ä/ɾ³ýÊÇÒ»ÖÖ¡°Åú´¦Àí²Ù×÷¡±**£º½¨Òé `BeginTransaction()` ºó¼¯Öд¦Àí£¬ÔÙ `Commit()`¡£ 3. **µ¥Ïß³ÌʹÓÃ**£º¼´Ê¹ÄÚ²¿ÓÐ `lock (this)`£¬Ò²²»½¨Òé¶àÏ̲߳¢·¢²Ù×÷ͬһ¸öʵÀý¡£ 4. **±íÍ·ÁÐÃûÓëÊôÐÔÃû**£ºÐ´ÈëʹÓà `SerialHelper.GetName`£¬¶ÁÈ¡ÊÇ°´ÁÐÃûÓ³Éäµ½ÊôÐÔ£»ÈôÄã×Ô¶¨ÒåÁÐÃû£¨ÐòÁл¯ÌØÐÔ£©£¬ÒªÈ·±£Ð´Èë/¶ÁÈ¡Ò»Ö¡£ --- ## 11. Ïà¹ØÁ´½Ó - ÔÚÏßÎĵµ£º`https://newlifex.com/core/csv_db` - Ô´Â룺`NewLife.Core/IO/CsvDb.cs` - ÒÀÀµ£º`NewLife.Core/IO/CsvFile.cs`