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/* 2021.10.14 */
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.OrmHelper;
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}'; password={_pass}; 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 bool Connect()
{
if (_db == null)
{
_db = new SQLiteConnection();
_db.ConnectionString = ConnectionString;
}
else
{
if (_db.State == ConnectionState.Open) return true;
}
try
{
_db.Open();
switch (_db.State)
{
case ConnectionState.Open: return true;
default: return false;
}
}
catch (Exception ex)
{
Logger.Error(nameof(Sqlite), "Connection", ex, _db.ConnectionString);
Close();
return false;
}
}
/// <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)
{
if (!Connect()) return "未连接。";
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) return Example.InvalidQueryConnection;
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(sql, _db))
{
const string name = "result";
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) return Example.InvalidExecuteConnection;
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())
{
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())
{
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())
{
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。
if (!Connect()) return "连接数据库失败。";
// 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 = GetColumnDeclaration(column);
if (type == TextUtility.Empty) return TextUtility.Merge("类型 ", column.Type.ToString(), " 不受支持。");
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)
{
if (record == null) return "参数无效。";
OrmHelper.FixProperties(record);
var structure = TableStructure.Parse(record.GetType());
if (structure == null) return "无法解析记录模型。";
var parameters = structure.CreateParameters(record, CreateDataParameter);
var sql = GenerateInsertStatement(structure.Name, (IEnumerable<IDataParameter>)parameters);
var execute = Execute(sql, parameters);
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)
{
if (record == null) return "参数无效。";
FixProperties(record);
SetUpdated(record);
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。";
var parameters = structure.CreateParameters(record, CreateDataParameter, "_key");
var sql = GenerateUpdateStatement(structure.Name, record.Key, parameters);
var execute = Execute(sql, parameters);
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) => OrmHelper.Query(this, model, sql);
/// <summary>获取按指定语句查询到的所有记录。</summary>
public Result<T[]> Query<T>(string sql) where T : class, new() => OrmHelper.Query<T>(this, sql);
/// <summary>查询多条记录。</summary>
public Result<object[]> Query(Type model, long flag = 0) => OrmHelper.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() => OrmHelper.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<IRecord> Get(Type model, string key, long flag = 0) => OrmHelper.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() => OrmHelper.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) => OrmHelper.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 GetColumnDeclaration(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.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("[", (object)column.Field, "] ", type);
}
/// <summary>创建参数。</summary>
/// <exception cref="ArgumentNullException"></exception>
/// <exception cref="InvalidOperationException"></exception>
public static SQLiteParameter CreateDataParameter(Parameter parameter)
{
if (parameter == null) throw new InvalidOperationException("参数无效。");
return CreateDataParameter(parameter.Name, parameter.Type, parameter.Size, parameter.Value);
}
/// <summary>创建参数。</summary>
public static SQLiteParameter CreateDataParameter(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 SQLiteParameter CreateDataParameter(string name, string type, int size, object value)
{
var v = value;
if (value is string && value != null && size > 0)
{
v = TextUtility.Left((string)value, size);
}
var p = new SQLiteParameter();
p.ParameterName = name;
p.TypeName = type;
p.Value = v;
p.Size = size;
return p;
}
/// <summary>创建参数。</summary>
public static SQLiteParameter CreateDataParameter(string name, string type, object value)
{
var p = new SQLiteParameter();
p.ParameterName = name;
p.TypeName = 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 "SQLite Backup Failed: Invalid Source";
if (destination == null) return "SQLite Backup Failed: Invalid Destination";
if (!source.Connect()) return "SQLite Backup Failed: Invalid Source Connection";
if (!destination.Connect()) return "SQLite Backup Failed: Invalid Destination Connection";
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>创建参数。</summary>
public static IDbDataParameter CreateParameter(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 CreateParameter(string field, DbType type, object value)
{
var p = new SQLiteParameter();
p.ParameterName = field;
p.DbType = type;
p.Value = value;
return p;
}
/// <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
#region 生成 SQL 语句
/// <summary>生成 INSERT INTO 语句。表名必须有效,无有效参数时将获取空结果。</summary>
/// <exception cref="System.ArgumentException"></exception>
/// <exception cref="System.ArgumentNullException"></exception>
public static string GenerateInsertStatement(string table, IEnumerable<IDataParameter> parameters)
{
if (table == null) throw new ArgumentNullException(nameof(table));
var t = TextUtility.AntiInject(table, 255);
if (TextUtility.IsBlank(t)) throw new ArgumentException("表名无效。", nameof(table));
var cs = GetParametersNames(parameters);
if (cs.Count < 1) return TextUtility.Empty;
return GenerateInsertStatement(t, cs);
}
private static string GetParameterName(string parameter)
{
var name = TextUtility.AntiInject(parameter, 255);
if (name.StartsWith("@") && name.Length > 1)
{
name = name.Substring(1, name.Length - 1);
}
return name;
}
private static string GetParameterName(IDataParameter parameter)
{
var name = TextUtility.Empty;
if (parameter != null)
{
name = GetParameterName(parameter.ParameterName);
}
return name;
}
private static List<string> GetParametersNames(IEnumerable<IDataParameter> parameters)
{
var columns = new List<string>();
if (parameters != null)
{
foreach (var parameter in parameters)
{
var name = GetParameterName(parameter);
var isblank = TextUtility.IsBlank(name);
if (isblank) continue;
columns.Add(name);
}
}
return columns;
}
private static string GenerateInsertStatement(string table, List<string> columns)
{
var r = TextUtility.Empty;
var t = TextUtility.AntiInject(table, 255);
if (columns != null && !TextUtility.IsBlank(t))
{
var count = 0;
var names = new List<string>();
var values = new List<string>();
foreach (var column in columns)
{
//names.Add(TextGenerator.Merge("[", column, "]"));
names.Add(TextUtility.Merge(column));
values.Add("@" + column);
count += 1;
}
var sb = new StringBuilder();
if (count > 0)
{
sb.Append("insert into [", t, "](", TextUtility.Join(", ", names), ") ");
sb.Append("values(", TextUtility.Join(", ", values), "); ");
}
r = sb.ToString();
}
return r;
}
private static string GenerateUpdateStatement(string table, string key, List<string> columns)
{
var result = TextUtility.Empty;
var t = TextUtility.AntiInject(table, 255);
var k = TextUtility.AntiInject(key, 255);
if (columns != null && !TextUtility.IsBlank(t) && !TextUtility.IsBlank(k))
{
var items = new List<string>();
foreach (var column in columns)
{
items.Add(TextUtility.Merge("[", column, "]=@", column));
}
if (items.Count > 0)
{
result = TextUtility.Merge("update [", t, "] set ", TextUtility.Join(", ", items), " where [_key]='", k, "'; ");
}
}
return result;
}
/// <summary>生成 UPDATE 语句,键字段名为“_key”。表名必须有效,键值必须有效,无有效参数时将获取空结果。</summary>
/// <exception cref="System.ArgumentException"></exception>
/// <exception cref="System.ArgumentNullException"></exception>
public static string GenerateUpdateStatement(string table, string key, IEnumerable<IDataParameter> parameters)
{
if (table == null) throw new ArgumentNullException("argTable");
var t = TextUtility.AntiInject(table, 255);
if (TextUtility.IsBlank(t)) throw new ArgumentException("表名无效。", nameof(table));
if (key == null) throw new ArgumentNullException("argKey");
var k = TextUtility.AntiInject(key, 255);
if (TextUtility.IsBlank(k)) throw new ArgumentException("键值无效。", nameof(key));
var columns = GetParametersNames(parameters);
if (columns.Count < 1) return TextUtility.Empty;
return GenerateUpdateStatement(t, k, columns);
}
#endregion
}
}