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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 : DbClient
{
#region 基础
private string _connstr = null;
private string _path = null;
private string _pass = null;
/// <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) : base(timeout)
{
_path = path.IsEmpty() ? Memory : path;
_pass = pass;
if (pass.IsEmpty()) _connstr = $"data source='{_path}'; version=3; ";
else _connstr = $"data source='{_path}'; password={_pass}; version=3; ";
}
#endregion
#region public
/// <summary></summary>
public override string[] StoreNames() => throw new NotImplementedException();
/// <summary></summary>
public override string[] TableNames() => TextColumn("select name from sqlite_master where type='table' order by name");
/// <summary></summary>
public override string[] ColumnNames(string tableName) => TextColumn($"pragma table_info('{tableName.SafeName()}'); ");
/// <summary>插入记录。返回错误信息。</summary>
public override 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 override 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 cs = new List<string>();
foreach (var p in ps) cs.Add($"[{p.ParameterName}] = @{p.ParameterName}");
var sql = $"update [{table}] set {string.Join(", ", cs.ToArray())} where [{structure.Key.Field}] = '{record.Key.SafeKey()}'";
// 执行。
var execute = Execute(sql, ps);
if (execute.Success && execute.Rows > 0) return TextUtility.Empty;
return execute.Message;
}
#endregion
#region protected
/// <summary></summary>
protected override string Initialize(TableStructure structure)
{
// 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></summary>
protected override string NewConnectionString() => _connstr;
/// <summary></summary>
protected override IDataAdapter CreateDataAdapter(IDbCommand command) => new SQLiteDataAdapter((SQLiteCommand)command);
/// <summary></summary>
protected override IDbConnection CreateConnection() => new SQLiteConnection();
/// <summary></summary>
protected override IDataParameter CreateParameter() => new SQLiteParameter();
/// <summary></summary>
protected override string KeysSql(string tableName, string keyField, string flagField, long flagValue)
{
if (flagValue == 0) return $"select [{keyField}] from [{tableName}] where [{flagField}] = {flagValue}";
return $"select [{keyField}] from [{tableName}]";
}
/// <summary></summary>
protected override string RecordSql(string tableName, string keyField, string keyValue, string flagField, long flagValue)
{
if (flagValue == 0) return $"select * from [{tableName}] where [{keyField}] = '{keyValue}' limit 1";
else return $"select * from [{tableName}] where [{keyField}] = '{keyValue}' and [{flagField}] = {flagValue} limit 1";
}
/// <summary></summary>
protected override string RecordsSql(string tableName, string flagField, long flagValue)
{
if (flagValue == 0) return $"select * from [{tableName}]";
else return $"select * from [{tableName}] where [{flagField}] = {flagValue}";
}
#endregion
#region special
/// <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:";
/// <summary>查询数据库中的所有视图名。</summary>
public string[] ViewNames() => TextColumn("select name from sqlite_master where type='view' order by name");
#endregion
#region mirror
/// <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));
/// <summary>备份数据库,返回错误信息。</summary>
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
{
var src = (SQLiteConnection)source.Connection;
var dst = (SQLiteConnection)destination.Connection;
src.BackupDatabase(dst, "main", "main", -1, null, 0);
return "";
}
catch (Exception ex)
{
return "SQLite Load Failed: " + ex.Message;
}
}
}
}
#endregion
#region type & parameter
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;
}
#endregion
}
}