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/* 2021.11.07 */
using System; using System.Collections.Generic; using System.Data; using System.Data.Common; using System.Data.SQLite; using System.Text; //using Mono.Data.Sqlite;
using static Apewer.Source.SourceUtility;
namespace Apewer.Source {
/// <summary>用于快速连接 SQLite 数据库的辅助。</summary>
public class Sqlite : IDbClient {
#region 基础
private Timeout _timeout = null; private string _connstring = ""; private string _path = ""; private string _pass = "";
private object _locker = new object();
/// <summary>获取或设置日志记录。</summary>
public Logger Logger { get; set; }
/// <summary>超时设定。</summary>
public Timeout Timeout { get => _timeout; }
/// <summary>创建连接实例。</summary>
/// <remarks>注意:<br />- 构造函数不会创建不存在的文件;<br />- 参数 path 为文件路径,指定为空时将使用 :memory: 作为路径连接内存。</remarks>
public Sqlite(string path = null, string pass = null, Timeout timeout = null) { _timeout = timeout ?? Timeout.Default; _path = path.IsEmpty() ? Memory : path; _pass = pass; if (pass.IsEmpty()) _connstring = $"data source='{_path}'; version=3; "; else _connstring = $"data source='{_path}'; password={_pass}; version=3; "; }
#endregion
#region 连接
private SQLiteConnection _db = null;
/// <summary>数据库已经连接。</summary>
public bool Online { get => _db != null && _db.State == ConnectionState.Open; }
/// <summary>连接字符串。</summary>
public string ConnectionString { get => _connstring; }
/// <summary>获取当前的 SQLiteConnection 对象。</summary>
public IDbConnection Connection { get => _db; }
/// <summary>连接数据库,若未连接则尝试连接。</summary>
/// <returns>是否已连接。</returns>
public string Connect() { if (_db == null) { _db = new SQLiteConnection(); _db.ConnectionString = ConnectionString; } else { if (_db.State == ConnectionState.Open) return null; } try { _db.Open(); switch (_db.State) { case ConnectionState.Open: return null; default: return $"连接失败,当前处于 {_db.State} 状态。"; } } catch (Exception ex) { Logger.Error(nameof(Sqlite), "Connection", ex, _db.ConnectionString); Close(); return ex.Message; } }
/// <summary>关闭连接,并释放对象所占用的系统资源。</summary>
public void Close() { if (_db != null) { if (_transaction != null) { if (_autocommit) Commit(); else Rollback(); } lock (_locker) { _db.Dispose(); } _db = null; } }
/// <summary>关闭连接,释放对象所占用的系统资源,并清除连接信息。</summary>
public void Dispose() { Close(); }
#endregion
#region Transaction
private IDbTransaction _transaction = null; private bool _autocommit = false;
/// <summary>启动事务。</summary>
public string Begin(bool commit = true) => Begin(commit, null);
/// <summary>启动事务。</summary>
public string Begin(bool commit, Class<IsolationLevel> isolation) { var connect = Connect(); if (connect.NotEmpty()) return connect; if (_transaction != null) return "存在已启动的事务,无法再次启动。"; try { _transaction = isolation ? _db.BeginTransaction(isolation.Value) : _db.BeginTransaction(); _autocommit = commit; return null; } catch (Exception ex) { Logger.Error(nameof(Sqlite), "Begin", ex.Message()); return ex.Message(); } }
/// <summary>提交事务。</summary>
public string Commit() { if (_transaction == null) return "事务不存在。"; try { _transaction.Commit(); RuntimeUtility.Dispose(_transaction); _transaction = null; return null; } catch (Exception ex) { RuntimeUtility.Dispose(_transaction); _transaction = null; Logger.Error(nameof(Sqlite), "Commit", ex.Message()); return ex.Message(); } }
/// <summary>从挂起状态回滚事务。</summary>
public string Rollback() { if (_transaction == null) return "事务不存在。"; try { _transaction.Rollback(); RuntimeUtility.Dispose(_transaction); _transaction = null; return null; } catch (Exception ex) { RuntimeUtility.Dispose(_transaction); _transaction = null; Logger.Error(nameof(Sqlite), "Rollback", ex.Message()); return ex.Message(); } }
#endregion
#region SQL
/// <summary>查询。</summary>
public IQuery Query(string sql) => Query(sql, null);
/// <summary>查询。</summary>
public IQuery Query(string sql, IEnumerable<IDataParameter> parameters) { if (string.IsNullOrEmpty(sql)) return Example.InvalidQueryStatement;
var connected = Connect(); if (connected.NotEmpty()) return new Query(false, connected);
var query = new Query(); try { using (var command = new SQLiteCommand()) { command.Connection = _db; command.CommandTimeout = _timeout.Query; command.CommandText = sql; if (parameters != null) { foreach (var p in parameters) { if (p != null) command.Parameters.Add(p); } } using (var dataset = new DataSet()) { using (var da = new SQLiteDataAdapter(command)) { var name = "table_" + Guid.NewGuid().ToString("n"); da.Fill(dataset, name); var table = dataset.Tables[name]; return new Query(table); } } } } catch (Exception ex) { Logger.Error(nameof(Sqlite), "Query", ex, sql); return new Query(ex); } }
/// <summary>执行单条 Transact-SQL 语句。</summary>
public IExecute Execute(string sql) => Execute(sql, null);
/// <summary>执行单条 Transact-SQL 语句,并加入参数。</summary>
public IExecute Execute(string sql, IEnumerable<IDataParameter> parameters) { if (string.IsNullOrEmpty(sql)) return Example.InvalidExecuteStatement;
var connected = Connect(); if (connected.NotEmpty()) return new Execute(false, connected);
lock (_locker) { var inTransaction = _transaction != null; if (!inTransaction) Begin(); try { using (var command = new SQLiteCommand()) { command.Connection = _db; command.Transaction = (SQLiteTransaction)_transaction; command.CommandTimeout = _timeout.Execute; command.CommandText = sql; if (parameters != null) { foreach (var p in parameters) { if (p != null) command.Parameters.Add(p); } } var rows = command.ExecuteNonQuery(); if (!inTransaction) Commit(); // todo 此处应该检查事务提交产生的错误。
return new Execute(true, rows); } } catch (Exception ex) { Logger.Error(nameof(Sqlite), "Execute", ex, sql); if (!inTransaction) Rollback(); return new Execute(ex); } } }
#endregion
#region 属性。
/// <summary>保存当前数据库到文件,若文件已存在则将重写文件。</summary>
public bool Save(string path, string pass = null) { if (!StorageUtility.CreateFile(path, 0, true)) { Logger.Error(nameof(Sqlite), "Save", TextUtility.Merge("创建文件 ", path, " 失败。")); return false; }
using (var destination = new Sqlite(path, pass)) return Save(destination); }
/// <summary>保存当前数据库到目标数据库。</summary>
public bool Save(Sqlite destination) => string.IsNullOrEmpty(Backup(this, destination));
/// <summary>加载文件到当前数据库。</summary>
public bool Load(string path, string pass = null) { using (var source = new Sqlite(path, pass)) return Load(source); }
/// <summary>加载源数据库到当前数据库。</summary>
public bool Load(Sqlite source) => string.IsNullOrEmpty(Backup(source, this));
#endregion
#region ORM
/// <summary>查询数据库中的所有表名。</summary>
public string[] TableNames() { var list = new List<string>(); if (Connect().IsEmpty()) { var sql = "select name from sqlite_master where type='table' order by name; "; var query = (Query)Query(sql); for (int r = 0; r < query.Rows; r++) { var cell = query.Text(r, 0); if (TextUtility.IsBlank(cell)) continue; list.Add(cell); } query.Dispose(); } return list.ToArray(); }
/// <summary>查询数据库中的所有视图名。</summary>
public string[] ViewNames() { var list = new List<string>(); if (Connect().IsEmpty()) { var sql = "select name from sqlite_master where type='view' order by name; "; var query = (Query)Query(sql); for (int r = 0; r < query.Rows; r++) { var cell = query.Text(r, 0); if (TextUtility.IsBlank(cell)) continue; list.Add(cell); } query.Dispose(); } return list.ToArray(); }
/// <summary>查询表中的所有列名。</summary>
public string[] ColumnNames(string table) { var list = new List<string>(); if (Connect().IsEmpty()) { var t = TextUtility.AntiInject(table); var sql = TextUtility.Merge("pragma table_info('", TextUtility.AntiInject(t), "'); "); using (var query = Query(sql) as Query) { for (int r = 0; r < query.Rows; r++) { var cell = query.Text(r, "name"); if (TextUtility.IsBlank(cell)) continue; list.Add(cell); } } } return list.ToArray(); }
/// <summary>创建表,不修改已存在表。成功时返回空字符串,发生异常时返回异常信息。</summary>
public string Initialize(Record model) => model == null ? "参数无效。" : Initialize(model.GetType());
/// <summary>创建表,不修改已存在表。成功时返回空字符串,发生异常时返回异常信息。</summary>
public string Initialize<T>() where T : class, new() => Initialize(typeof(T));
/// <summary>创建表,不修改已存在表。当现存表中缺少模型中属性对应的列时增加列。成功时返回空字符串,发生异常时返回异常信息。</summary>
public string Initialize(Type model) { var structure = TableStructure.Parse(model); if (structure == null) return "无法解析记录模型。";
// 连接数据库。
var connect = Connect(); if (connect.NotEmpty()) return connect;
// 检查现存表。
var exists = false; var tables = TableNames(); if (tables.Length > 0) { var lower = structure.Name.ToLower(); foreach (var table in tables) { if (TextUtility.IsBlank(table)) continue; if (table.ToLower() == lower) { exists = true; break; } } }
if (exists) { return TextUtility.Merge("指定的表已经存在。"); } else { var sqlcolumns = new List<string>(); foreach (var column in structure.Columns) { var type = Declaration(column); if (string.IsNullOrEmpty(type)) { return TextUtility.Merge("类型 ", column.Type.ToString(), " 不受支持。"); }
if (!column.Independent) { if (column.PrimaryKey) type = type + " primary key"; }
sqlcolumns.Add(type); } var sql = TextUtility.Merge("create table [", structure.Name, "](", TextUtility.Join(", ", sqlcolumns), "); "); var execute = Execute(sql); if (execute.Success) return TextUtility.Empty; return execute.Message; } }
/// <summary>插入记录。返回错误信息。</summary>
public string Insert(object record, string table = null) { if (record == null) return "参数无效。"; SourceUtility.FixProperties(record);
// 解析模型,获取表名。
var structure = TableStructure.Parse(record.GetType()); if (structure == null) return "无法解析记录模型。"; if (string.IsNullOrEmpty(table)) table = structure.Name; if (string.IsNullOrEmpty(table)) return "表名称无效。";
// 排除字段。
var excluded = new List<string>(); foreach (var ca in structure.Columns) { // 排除不使用 ORM 的属性。
if (ca.Independent || ca.Incremental) excluded.Add(ca.Field); }
// 准备参数。
var ps = structure.CreateParameters(record, Parameter, excluded); var psc = ps.Length; if (psc < 1) return "数据模型不包含字段。";
// 合成 SQL 语句。
var sb = new StringBuilder(); sb.Append("insert into ["); sb.Append(table); sb.Append("]("); for (var i = 0; i < psc; i++) { if (i > 0) sb.Append(", "); sb.Append(ps[i].ParameterName); } sb.Append(") values("); for (var i = 0; i < psc; i++) { if (i > 0) sb.Append(", "); sb.Append("@"); sb.Append(ps[i].ParameterName); } sb.Append("); "); var sql = sb.ToString();
// 执行。
var execute = Execute(sql, ps); if (execute.Success && execute.Rows > 0) return TextUtility.Empty; return execute.Message; }
/// <summary>更新记录,实体中的 Key 属性不被更新。返回错误信息。</summary>
/// <remarks>无法更新带有 Independent 特性的模型(缺少 Key 属性)。</remarks>
public string Update(IRecord record, string table = null) { if (record == null) return "参数无效。"; FixProperties(record); SetUpdated(record);
// 解析模型,获取表名。
var structure = TableStructure.Parse(record.GetType()); if (structure == null) return "无法解析记录模型。"; if (structure.Independent) return "无法更新带有 Independent 特性的模型。"; if (string.IsNullOrEmpty(table)) table = structure.Name; if (string.IsNullOrEmpty(table)) return "表名称无效。";
// 排除字段。
var excluded = new List<string>(); if (structure.Key != null) excluded.Add(structure.Key.Field); foreach (var ca in structure.Columns) { // 排除不使用 ORM 的属性、自增属性和主键属性。
if (ca.Independent || ca.Incremental || ca.PrimaryKey) excluded.Add(ca.Field); }
// 准备参数。
var ps = structure.CreateParameters(record, Parameter, excluded); var psc = ps.Length; if (psc < 1) return "数据模型不包含字段。";
// 合成 SQL 语句。
var sb = new StringBuilder(); sb.Append("update ["); sb.Append(table); sb.Append("] set "); for (var i = 0; i < psc; i++) { if (i > 0) sb.Append(", "); sb.Append("["); sb.Append(ps[i].ParameterName); sb.Append("] = @"); sb.Append(ps[i].ParameterName); } sb.Append(" where [_key] = '"); sb.Append(record.Key.SafeKey()); sb.Append("'; "); var sql = sb.ToString();
// 执行。
var execute = Execute(sql, ps); if (execute.Success && execute.Rows > 0) return TextUtility.Empty; return execute.Message; }
/// <summary>获取按指定语句查询到的所有记录。</summary>
public Result<object[]> Query(Type model, string sql, IEnumerable<IDataParameter> parameters = null) => SourceUtility.Query(this, model, sql, parameters);
/// <summary>获取按指定语句查询到的所有记录。</summary>
public Result<T[]> Query<T>(string sql, IEnumerable<IDataParameter> parameters = null) where T : class, new() { var query = Query(sql); if (!query.Success) return new Result<T[]>(query.Message); var records = query.Fill<T>(); query.Dispose();
var result = new Result<T[]>(records); return result; }
/// <summary>查询多条记录。</summary>
public Result<object[]> Query(Type model, long flag = 0) => SourceUtility.Query(this, model, (tn) => { if (flag == 0) return $"select * from [{tn}]; "; return $"select * from [{tn}] where _flag={flag}; "; });
/// <summary>查询多条记录。</summary>
public Result<T[]> Query<T>(long flag = 0) where T : class, IRecord, new() => SourceUtility.Query<T>(this, (tn) => { if (flag == 0) return $"select * from [{tn}]; "; return $"select * from [{tn}] where _flag={flag}; "; });
/// <summary>获取具有指定 Key 的记录。</summary>
public Result<object> Get(Type model, string key, long flag = 0) => SourceUtility.Get(this, model, key, (tn, sk) => { if (flag == 0) return $"select * from [{tn}] where _key='{sk}' limit 1; "; return $"select * from [{tn}] where _flag={flag} and _key='{sk}' limit 1; "; });
/// <summary>获取具有指定 Key 的记录。</summary>
public Result<T> Get<T>(string key, long flag) where T : class, IRecord, new() => SourceUtility.Get<T>(this, key, (tn, sk) => { if (flag == 0) return $"select * from [{tn}] where _key='{sk}' limit 1; "; return $"select * from [{tn}] where _flag={flag} and _key='{sk}' limit 1; "; });
/// <summary>获取指定类型的主键,按 Flag 属性筛选。</summary>
public Result<string[]> Keys(Type model, long flag = 0) => SourceUtility.Keys(this, model, (tn) => { if (flag == 0) return $"select _key from [{tn}] where _flag={flag}; "; return $"select _key from [{tn}]; "; });
/// <summary>>获取指定类型的主键,按 Flag 属性筛选。</summary>
public Result<string[]> Keys<T>(long flag = 0) where T : class, IRecord, new() => Keys(typeof(T), flag);
#endregion
#region static
/// <summary>对文本转义,符合 SQL 安全性。可根据字段类型限制 UTF-8 字节数,默认为 0 时不限制字节数。</summary>
public static string Escape(string text, int bytes = 0) { if (text.IsEmpty()) return "";
var t = text ?? ""; t = t.Replace("\\", "\\\\"); t = t.Replace("'", "\\'"); t = t.Replace("\n", "\\n"); t = t.Replace("\r", "\\r"); t = t.Replace("\b", "\\b"); t = t.Replace("\t", "\\t"); t = t.Replace("\f", "\\f");
if (bytes > 5) { if (t.Bytes(Encoding.UTF8).Length > bytes) { while (true) { t = t.Substring(0, t.Length - 1); if (t.Bytes(Encoding.UTF8).Length <= (bytes - 4)) break; } t = t + " ..."; } }
return t; }
private static string GetColumnTypeName(ColumnType type) { switch (type) { case ColumnType.Bytes: return "blob"; case ColumnType.Integer: return "integer"; case ColumnType.Float: return "float"; case ColumnType.VarChar: case ColumnType.VarChar191: case ColumnType.VarCharMax: return "varchar"; case ColumnType.Text: return "text"; case ColumnType.NVarChar: case ColumnType.NVarChar191: case ColumnType.NVarCharMax: return "nvarchar"; case ColumnType.NText: return "ntext"; default: return null; } }
private static string Declaration(ColumnAttribute column) { var type = TextUtility.Empty; var length = NumberUtility.Restrict(column.Length, 0, 255).ToString(); switch (column.Type) { case ColumnType.Bytes: type = "blob"; break; case ColumnType.Integer: type = "integer"; break; case ColumnType.Float: type = "real"; break; case ColumnType.DateTime: type = "datetime"; break; case ColumnType.VarChar: type = TextUtility.Merge("varchar(", length, ")"); break; case ColumnType.VarChar191: type = TextUtility.Merge("varchar(191)"); break; case ColumnType.VarCharMax: type = TextUtility.Merge("varchar(255)"); break; case ColumnType.Text: type = TextUtility.Merge("text"); break; case ColumnType.NVarChar: type = TextUtility.Merge("nvarchar(", length, ")"); break; case ColumnType.NVarChar191: type = TextUtility.Merge("nvarchar(191)"); break; case ColumnType.NVarCharMax: type = TextUtility.Merge("nvarchar(255)"); break; case ColumnType.NText: type = TextUtility.Merge("ntext"); break; default: return TextUtility.Empty; } return TextUtility.Merge("[", column.Field, "] ", type); }
/// <summary>创建参数。</summary>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="InvalidOperationException"></exception>
public static SQLiteParameter Parameter(Parameter parameter) { if (parameter == null) throw new InvalidOperationException("参数无效。"); return Parameter(parameter.Name, parameter.Type, parameter.Size, parameter.Value); }
/// <summary>创建参数。</summary>
public static SQLiteParameter Parameter(string name, ColumnType type, int size, object value) { var n = TextUtility.Trim(name); if (TextUtility.IsBlank(n)) return null;
var t = GetColumnTypeName(type);
var s = size; switch (type) { case ColumnType.VarChar: s = NumberUtility.Restrict(s, 0, 8000); break; case ColumnType.NVarChar: s = NumberUtility.Restrict(s, 0, 4000); break; case ColumnType.VarChar191: case ColumnType.NVarChar191: s = NumberUtility.Restrict(s, 0, 191); break; case ColumnType.VarCharMax: case ColumnType.NVarCharMax: s = NumberUtility.Restrict(s, 0, 255); break; default: s = 0; break; }
var v = value; if (v is string && v != null && s > 0) { v = TextUtility.Left((string)v, s); }
var p = new SQLiteParameter(); p.ParameterName = n; p.TypeName = t; p.Value = v; if (s > 0) p.Size = s; return p; }
/// <summary>创建参数。</summary>
public static IDbDataParameter Parameter(string field, DbType type, int size, object value) { var p = new SQLiteParameter(); p.ParameterName = field; p.DbType = type; p.Size = size; p.Value = value; return p; }
/// <summary>创建参数。</summary>
public static IDbDataParameter Parameter(string field, DbType type, object value) { var p = new SQLiteParameter(); p.ParameterName = field; p.DbType = type; p.Value = value; return p; }
/// <summary>备份数据库,返回错误信息。</summary>
public static string Backup(Sqlite source, Sqlite destination) { if (source == null) return "备份失败:源无效。"; if (destination == null) return "备份失败:目标无效。"; var sConnect = source.Connect(); if (sConnect.NotEmpty()) return sConnect; var dConnect = source.Connect(); if (dConnect.NotEmpty()) return dConnect;
lock (source._locker) { lock (destination._locker) { try { source._db.BackupDatabase(destination._db, "main", "main", -1, null, 0); return ""; } catch (Exception ex) { return "SQLite Load Failed: " + ex.Message; } } } }
/// <summary>整理数据库,压缩未使用的空间。</summary>
public const string Vacuum = "vacuum";
/// <summary>内存数据库的地址。</summary>
public const string Memory = ":memory:";
#endregion
}
}
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