xuyueandClaude Opus 5.5
670abe5921
- 每个学生一套数据库，长期保存（data/databases/<用户编号>/库名.db）；学生程序运行时挂进沙箱可读写 - Sim.Data：SqlConnection / SqlCommand / SqlDataReader / SqlDataAdapter / SqlCommandBuilder / SqlParameter； 连接字符串只按库名打开学生自己的库；ScriptDom 解析 T-SQL 后按白名单转写成 SQLite 语句， STRICT 表 + 元数据表还原 SQL Server 的列类型，报错编号和中文信息与 SQL Server 一致； INSERT 不写列名时跳过自增列，日期统一格式（书上 DateTime.ToString() 拼接的日期能正确比较） - 常驻 SQL 服务（Sim.Runner sql-server）：数据库页面的查询、对象资源管理器，评分前按实验 database.sql 建库 - 数据库页面（代替 SSMS）：对象资源管理器、查询窗口、编辑前 200 行、表设计器、恢复实验初始数据 - DataGridView（绑定 DataView/DataTable/DataSet，单元格修改写回 DataTable）、DateTimePicker；设计器工具箱加入 - 评分：每个检查项一份新建的实验库；新增点 / 修改表格单元格、选日期、表格里有 / 没有某行的检查 - 示例：项目 6 任务 2、3；时间格式改成和中文 Windows 一致（9:05:03）；异常堆栈不暴露服务器路径 - 测试：数据库端到端、接口（每人只看到自己的库、恢复实验数据）、评分出错情况、T-SQL 生成 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
244 lines
11 KiB
C#
244 lines
11 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Data.SqlClient;
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using System.Linq;
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using System.Text.RegularExpressions;
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using Microsoft.Data.Sqlite;
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using Microsoft.SqlServer.TransactSql.ScriptDom;
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namespace Sim.Data.Engine;
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/// <summary>结果集的一列：名字、T-SQL 类型（表达式列为 null），以及来自哪张表的哪一列（SqlCommandBuilder 生成语句时要用）</summary>
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internal sealed record ResultColumn(string Name, TSqlType? Type, string? BaseTable, string? BaseColumn, bool IsKey, bool IsIdentity, bool AllowNull)
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{
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public Type ClrType => Type?.ClrType is { } t && t != typeof(object) ? t : typeof(object);
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}
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/// <summary>一个结果集（读完放在内存里）</summary>
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internal sealed record QueryResult(IReadOnlyList<ResultColumn> Columns, List<object[]> Rows);
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/// <summary>一批语句的执行结果：各个结果集和受影响的行数（只有增删改时才算，否则为 -1）</summary>
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internal sealed record BatchResult(List<QueryResult> Results, int RecordsAffected);
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/// <summary>
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/// 一个打开的数据库连接：当前库（USE 可以切换）、事务，执行一批 T-SQL。
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/// SqlConnection 和数据库页面的查询窗口都用它。
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/// </summary>
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internal sealed class Session : IDisposable
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{
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private SqliteTransaction? _transaction;
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private long _deadline = long.MaxValue;
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public Session(DatabaseStore store, string database, TimeSpan? timeLimit = null)
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{
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Store = store;
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TimeLimit = timeLimit;
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Connection = Open(database);
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Database = store.Resolve(database)!;
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}
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/// <summary>每批语句最长执行时间（数据库页面的查询窗口用；学生程序里由沙箱的 CPU 时间限制兜底）</summary>
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public TimeSpan? TimeLimit { get; }
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private SqliteConnection Open(string database)
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{
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var connection = Store.Open(database);
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if (TimeLimit != null)
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{
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// 每执行一千条虚拟机指令检查一次，超时就中断（SQLite 报 interrupted）
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SQLitePCL.raw.sqlite3_progress_handler(connection.Handle, 1000, _ => Environment.TickCount64 > _deadline ? 1 : 0, null);
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}
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return connection;
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}
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public DatabaseStore Store { get; }
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public SqliteConnection Connection { get; private set; }
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public string Database { get; private set; }
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public bool InTransaction => _transaction != null;
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public TableInfo? Lookup(string table) => DatabaseStore.GetTable(Connection, table);
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public void ChangeDatabase(string name)
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{
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if (Store.Resolve(name) == null) throw SqlException.DatabaseNotFound(name);
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if (_transaction != null) throw new SqlException(226, "在多语句事务内不允许使用 USE 语句。");
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var next = Open(name);
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Connection.Dispose();
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Connection = next;
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Database = Store.Resolve(name)!;
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}
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public void BeginTransaction()
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{
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if (_transaction != null) throw new InvalidOperationException("SqlConnection 不支持并行事务。");
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_transaction = Connection.BeginTransaction();
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}
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public void Commit()
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{
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_transaction?.Commit();
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_transaction = null;
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}
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public void Rollback()
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{
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_transaction?.Rollback();
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_transaction = null;
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}
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/// <summary>执行一批语句；parameter 按名字（带不带 @ 都行）取参数值</summary>
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public BatchResult Execute(string sql, Func<string, (bool Found, object? Value)> parameter)
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{
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var statements = Translator.Parse(sql);
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if (TimeLimit is { } limit) _deadline = Environment.TickCount64 + (long)limit.TotalMilliseconds;
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var results = new List<QueryResult>();
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var affected = -1;
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foreach (var parsed in statements)
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{
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var statement = Translate(parsed);
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switch (statement)
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{
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case CreateDatabase create:
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Store.Create(create.Name);
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break;
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case DropDatabases drop:
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foreach (var name in drop.Names)
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{
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if (string.Equals(Store.Resolve(name), Database, StringComparison.OrdinalIgnoreCase)) throw SqlException.DatabaseInUse(name);
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Store.Drop(name);
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}
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break;
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case UseDatabase use:
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ChangeDatabase(use.Name);
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break;
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case SqliteStatement run:
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var (result, changes) = Run(run, parameter);
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if (result != null) results.Add(result);
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else if (changes >= 0) affected = Math.Max(affected, 0) + changes;
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break;
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}
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}
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return new BatchResult(results, affected);
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}
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private Statement Translate(TSqlStatement statement)
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{
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try
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{
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return Translator.Translate(statement, Lookup);
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}
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catch (SqliteException ex)
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{
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throw Map(ex);
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}
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}
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private (QueryResult? Result, int Changes) Run(SqliteStatement statement, Func<string, (bool Found, object? Value)> parameter)
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{
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using var command = Connection.CreateCommand();
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command.Transaction = _transaction;
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command.CommandText = statement.Sql;
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foreach (var name in statement.Parameters)
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{
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var (found, value) = parameter(name);
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if (!found) throw SqlException.UndeclaredVariable(name);
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command.Parameters.AddWithValue(name, Values.ToStorage(value) ?? DBNull.Value);
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}
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// 建表等语句和元数据一起提交；已经在学生的事务里时就用那个事务
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var own = _transaction == null && statement.AfterExecute != null ? Connection.BeginTransaction() : null;
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if (own != null) command.Transaction = own;
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try
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{
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QueryResult? result = null;
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int changes;
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if (statement.IsQuery)
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{
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result = Read(command);
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changes = -1;
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}
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else
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{
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changes = command.ExecuteNonQuery();
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statement.AfterExecute?.Invoke(Connection);
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if (statement.AfterExecute != null) changes = -1;
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}
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own?.Commit();
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return (result, changes);
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}
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catch (SqliteException ex)
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{
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own?.Rollback();
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throw Map(ex);
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}
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finally
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{
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own?.Dispose();
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}
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}
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private QueryResult Read(SqliteCommand command)
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{
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using var reader = command.ExecuteReader();
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var schema = reader.GetSchemaTable();
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var tables = new Dictionary<string, TableInfo?>(StringComparer.OrdinalIgnoreCase);
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var columns = new List<ResultColumn>();
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for (var i = 0; i < reader.FieldCount; i++)
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{
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var row = schema.Rows[i];
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var baseTable = row["BaseTableName"] as string;
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var baseColumn = row["BaseColumnName"] as string;
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ColumnInfo? info = null;
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if (!string.IsNullOrEmpty(baseTable) && !string.IsNullOrEmpty(baseColumn))
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{
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if (!tables.TryGetValue(baseTable, out var table)) tables[baseTable] = table = Lookup(baseTable);
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info = table?.Find(baseColumn);
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}
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columns.Add(new ResultColumn(reader.GetName(i), info?.Type, info != null ? baseTable : null, info?.Name,
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info?.PrimaryKey ?? false, info?.Identity ?? false, info?.Nullable ?? true));
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}
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var rows = new List<object[]>();
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while (reader.Read())
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{
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var values = new object[reader.FieldCount];
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reader.GetValues(values);
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for (var i = 0; i < values.Length; i++) values[i] = Values.FromStorage(values[i], columns[i].Type);
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rows.Add(values);
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}
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return new QueryResult(columns, rows);
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}
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/// <summary>SQLite 的报错转成 SQL Server 的错误号和中文信息</summary>
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private SqlException Map(SqliteException ex)
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{
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if (Functions.TakePending() is { } pending) return pending;
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var message = ex.Message;
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Match m;
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if ((m = Regex.Match(message, @"no such table: (?:main\.)?(.+?)'?$")).Success) return SqlException.InvalidObject(m.Groups[1].Value);
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// SQLite 对写错的列名会附带"是不是想写字符串"的提示，只取列名本身
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if ((m = Regex.Match(message, @"no such column: ""?([^""\s']+)")).Success) return SqlException.InvalidColumn(m.Groups[1].Value);
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if ((m = Regex.Match(message, @"ambiguous column name: (.+?)'?$")).Success) return SqlException.AmbiguousColumn(m.Groups[1].Value);
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if ((m = Regex.Match(message, @"UNIQUE constraint failed: (\w+)\.")).Success) return SqlException.DuplicateKey(m.Groups[1].Value);
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if ((m = Regex.Match(message, @"NOT NULL constraint failed: (.+?)\.(.+?)'?$")).Success)
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return SqlException.NullNotAllowed(m.Groups[2].Value, $"{Database}.dbo.{m.Groups[1].Value}");
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if (message.Contains("CHECK constraint failed: trunc:")) return SqlException.Truncated();
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if ((m = Regex.Match(message, @"CHECK constraint failed: bit:(.+?)'?$")).Success) return new SqlException(245, $"列 '{m.Groups[1].Value}' 是 bit 类型，只能保存 0、1 或 NULL。");
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if ((m = Regex.Match(message, @"cannot store (\w+) value in (\w+) column (.+?)\.(.+?)'?$")).Success)
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{
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var type = Lookup(m.Groups[3].Value)?.Find(m.Groups[4].Value)?.Type.Name ?? m.Groups[2].Value.ToLowerInvariant();
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return new SqlException(245, $"将数据插入列 '{m.Groups[4].Value}' 时，无法把值转换成数据类型 {type}。");
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}
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if (message.Contains("database or disk is full")) return new SqlException(1105, "数据库已满：每个数据库最多约 50 MB。");
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if (message.Contains("misuse of aggregate")) return new SqlException(147, "聚合不应出现在 WHERE 子句中，除非该聚合位于 HAVING 子句或选择列表所包含的子查询中。");
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if (message.Contains("interrupted")) return new SqlException(-2, $"执行超时：查询超过 {TimeLimit?.TotalSeconds ?? 0} 秒，已停止。检查是否缺少 WHERE 条件或连接条件。");
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if (message.Contains("database is locked")) return new SqlException(1222, "已超过了锁请求超时时段：数据库正被其他程序修改，请稍后再试。");
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return new SqlException(50000, "执行出错：" + message.Replace("SQLite Error ", "").Trim());
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}
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public void Dispose()
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{
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_transaction?.Dispose();
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Connection.Dispose();
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}
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}
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