protected virtual IExpression VisitTable(TableIdentifier table)
{
if (table.IsTemporary)
{
_output.Append(table.Name);
}
else
{
_output.Append(this.GetIdentifier(table.Name));
}
if (!string.IsNullOrEmpty(table.Alias) && !string.Equals(table.Name, table.Alias))
{
_output.Append(" AS " + table.Alias);
}
return(table);
}
public static ISource From(this IStatement statement, TableIdentifier origin, string memberPath, Func<ISource, IDataEntityComplexProperty, ISource> subqueryFactory, out IDataEntityProperty property)
{
var found = origin.Reduce(memberPath, ctx =>
{
var source = ctx.Source;
if(ctx.Ancestors != null)
{
foreach(var ancestor in ctx.Ancestors)
{
source = statement.Join(source, ancestor, ctx.Path);
}
}
if(ctx.Property.IsComplex)
{
var complex = (IDataEntityComplexProperty)ctx.Property;
if(complex.Multiplicity == DataAssociationMultiplicity.Many)
{
if(subqueryFactory != null)
return subqueryFactory(source, complex);
//如果不允许一对多的子查询则抛出异常
throw new DataException($"The specified '{ctx.FullPath}' member is a one-to-many composite(navigation) property that cannot appear in the sorting and specific condition clauses.");
}
source = statement.Join(source, complex, ctx.FullPath);
}
return source;
});
if(found.IsFailed)
throw new DataException($"The specified '{memberPath}' member does not exist in the '{origin.Entity?.Name}' entity and it's inherits.");
//输出找到的属性元素
property = found.Property;
//返回找到的源
return found.Source;
}
private void Join(DeleteStatement statement, TableIdentifier table, SchemaMember schema)
{
if (table == null || schema == null || schema.Token.Property.IsSimplex)
{
return;
}
//不可变复合属性不支持任何写操作，即在删除操作中不能包含不可变复合属性
if (schema.Token.Property.Immutable)
{
throw new DataException($"The '{schema.FullPath}' is an immutable complex(navigation) property and does not support the delete operation.");
}
var join = statement.Join(table, schema);
var target = (TableIdentifier)join.Target;
statement.Tables.Add(target);
//生成当前导航属性表的继承链关联集
var joins = this.Join(statement, target, schema.FullPath);
if (schema.HasChildren)
{
foreach (var child in schema.Children)
{
if (joins != null)
{
join = joins.FirstOrDefault(j => ((TableIdentifier)j.Target).Entity == child.Token.Property.Entity);
if (join != null)
{
target = (TableIdentifier)join.Target;
}
}
this.Join(statement, target, child);
}
}
}
private void BuildSchema(DataUpdateContext context, UpdateStatement statement, TableIdentifier table, object data, SchemaMember member)
{
//如果不允许更新主键，则忽略对主键修改的构建
if (member.Token.Property.IsPrimaryKey && !context.Options.HasBehaviors(UpdateBehaviors.PrimaryKey))
{
return;
}
//确认指定成员是否有必须的写入值
var provided = context.Validate(member.Token.Property, out var value);
//如果不是批量更新，并且指定成员不是必须要生成的且也没有必须写入的值，则返回
if (!context.IsMultiple && !Utility.IsGenerateRequired(ref data, member.Name) && !provided)
{
return;
}
if (member.Token.Property.IsSimplex)
{
//忽略不可变属性
if (member.Token.Property.Immutable && !provided)
{
return;
}
//创建当前单值属性的对应的字段标识
var field = table.CreateField(member.Token);
if (typeof(Operand).IsAssignableFrom(member.Token.MemberType))
{
var operand = (Operand)member.Token.GetValue(data);
var expression = this.OperandConverter.Convert(context, statement, operand);
statement.Fields.Add(new FieldValue(field, expression));
}
else
{
var parameter = provided ?
Expression.Parameter(field, member, value) :
Expression.Parameter(field, member);
statement.Parameters.Add(parameter);
//如果当前的数据成员类型为递增步长类型则生成递增表达式
if (member.Token.MemberType == typeof(Interval))
{
/*
* 注：默认参数类型为对应字段的类型，而该字段类型可能为无符号数，
* 因此当参数类型为无符号数并且步长为负数(递减)，则可能导致参数类型转换溢出，
* 所以必须将该参数类型重置为有符号整数。
*/
parameter.DbType = System.Data.DbType.Int32;
//字段设置项的值为「字段+参数」的加法表达式
statement.Fields.Add(new FieldValue(field, field.Add(parameter)));
}
else
{
//字段设置项的值即为参数
statement.Fields.Add(new FieldValue(field, parameter));
}
}
}
else
{
//不可变复合属性不支持任何写操作，即在修改操作中不能包含不可变复合属性
if (member.Token.Property.Immutable)
{
throw new DataException($"The '{member.FullPath}' is an immutable complex(navigation) property and does not support the update operation.");
}
var complex = (IDataEntityComplexProperty)member.Token.Property;
if (complex.Multiplicity == DataAssociationMultiplicity.Many)
{
//注：在构建一对多的导航属性的UPSERT语句时不能指定容器数据(即data参数值为空)，因为批量操作语句不支持在构建阶段绑定到具体数据
var upserts = UpsertStatementBuilder.BuildUpserts(context, complex.Foreign, null, member, member.Children);
//将新建的语句加入到主语句的从属集中
foreach (var upsert in upserts)
{
statement.Slaves.Add(upsert);
}
}
else
{
if (context.Source.Features.Support(Feature.Updation.Multitable))
{
this.BuildComplex(context, statement, data, member);
}
else
{
this.BuildComplexStandalone(context, statement, data, member);
}
}
}
}
/// <summary>
/// <para>从指定的表标识对应的实体开始进行路径展开。</para>
/// <para>注：展开过程包括对父实体的属性集的搜索。</para>
/// </summary>
/// <param name="table">指定的进行展开的起点。</param>
/// <param name="path">指定要展开的成员路径，支持多级导航属性路径。</param>
/// <param name="step">指定路径中每个属性的展开回调函数。</param>
/// <returns>返回找到的结果。</returns>
public static ReduceResult Reduce(this TableIdentifier table, string path, Func <ReduceContext, ISource> step = null)
{
if (table == null)
{
throw new ArgumentNullException(nameof(table));
}
if (table.Entity == null)
{
throw new DataException($"The '{table}' table cannot be expanded.");
}
if (string.IsNullOrEmpty(path))
{
return(ReduceResult.Failure(table));
}
ICollection <IEntityMetadata> ancestors = null;
IEntityPropertyMetadata property = null;
ISource token = table;
var parts = path.Split('.');
var properties = table.Entity.Properties;
for (int i = 0; i < parts.Length; i++)
{
if (properties == null)
{
return(ReduceResult.Failure(token));
}
//如果当前属性集合中不包含指定的属性，则尝试从父实体中查找
if (!properties.TryGet(parts[i], out property))
{
//尝试从父实体中查找指定的属性
property = FindBaseProperty(ref properties, parts[i], ref ancestors);
//如果父实体中也不含指定的属性则返回失败
if (property == null)
{
return(ReduceResult.Failure(token));
}
}
//如果回调函数不为空，则调用匹配回调函数
//注意：将回调函数返回的结果作为下一次的用户数据保存起来
if (step != null)
{
token = step(new ReduceContext(string.Join(".", parts, 0, i), token, property, ancestors));
}
//清空继承实体链
if (ancestors != null)
{
ancestors.Clear();
}
if (property.IsSimplex)
{
break;
}
else
{
properties = GetAssociatedProperties((IEntityComplexPropertyMetadata)property, ref ancestors);
}
}
//返回查找到的结果
return(new ReduceResult(token, property));
}
private void BuildSchema(DataUpdateContext context, UpdateStatement statement, TableIdentifier table, object data, SchemaMember member)
{
//忽略主键修改，即不能修改主键
if (member.Token.Property.IsPrimaryKey)
{
return;
}
//如果不是批量更新，并且当前成员没有改动则返回
if (!context.IsMultiple && !this.HasChanges(data, member.Name))
{
return;
}
if (member.Token.Property.IsSimplex)
{
var field = table.CreateField(member.Token);
var parameter = Expression.Parameter(ParameterExpression.Anonymous, member, field);
statement.Fields.Add(new FieldValue(field, parameter));
statement.Parameters.Add(parameter);
}
else
{
var complex = (IEntityComplexPropertyMetadata)member.Token.Property;
if (complex.Multiplicity == AssociationMultiplicity.Many)
{
this.BuildUpsertion(statement, member);
}
else
{
table = this.Join(statement, member);
if (member.HasChildren)
{
foreach (var child in member.Children)
{
BuildSchema(context, statement, table, member.Token.GetValue(data), child);
}
}
}
}
}
protected StatementBase(TableIdentifier table)
{
this.Table = table ?? throw new ArgumentNullException(nameof(table));
}
public SubqueryStatement(IStatementBase host, TableIdentifier table) : base(table)
{
this.Host = host ?? throw new ArgumentNullException(nameof(host));
}
public ISelectStatementBase Subquery(TableIdentifier table)
{
return(new SubqueryStatement(this, table));
}
private void BuildSchema(DataUpdateContext context, UpdateStatement statement, TableIdentifier table, object data, SchemaMember member)
{
//忽略主键修改，即不能修改主键
if (member.Token.Property.IsPrimaryKey)
{
return;
}
//确认指定成员是否有必须的写入值
var provided = context.Validate(member.Token.Property, out var value);
//如果不是批量更新，并且指定成员不是必须要生成的且也没有必须写入的值，则返回
if (!context.IsMultiple && !Utility.IsGenerateRequired(ref data, member.Name) && !provided)
{
return;
}
if (member.Token.Property.IsSimplex)
{
//忽略不可变属性
if (member.Token.Property.Immutable && !provided)
{
return;
}
var field = table.CreateField(member.Token);
var parameter = provided ?
Expression.Parameter(field, member, value) :
Expression.Parameter(field, member);
//如果当前的数据成员类型为递增步长类型则生成递增表达式
if (member.Token.MemberType == typeof(Interval))
{
/*
* 注：默认参数类型为对应字段的类型，而该字段类型可能为无符号数，
* 因此当参数类型为无符号数并且步长为负数(递减)，则可能导致参数类型转换溢出，
* 所以必须将该参数类型重置为有符号整数。
*/
parameter.DbType = System.Data.DbType.Int32;
//字段设置项的值为字段加参数的加法表达式
statement.Fields.Add(new FieldValue(field, field.Add(parameter)));
}
else
{
statement.Fields.Add(new FieldValue(field, parameter));
}
statement.Parameters.Add(parameter);
}
else
{
//不可变复合属性不支持任何写操作，即在修改操作中不能包含不可变复合属性
if (member.Token.Property.Immutable)
{
throw new DataException($"The '{member.FullPath}' is an immutable complex(navigation) property and does not support the update operation.");
}
var complex = (IDataEntityComplexProperty)member.Token.Property;
if (complex.Multiplicity == DataAssociationMultiplicity.Many)
{
var upserts = UpsertStatementBuilder.BuildUpserts(context, complex.Foreign, data, member, member.Children);
//将新建的语句加入到主语句的从属集中
foreach (var upsert in upserts)
{
statement.Slaves.Add(upsert);
}
}
else
{
if (context.Source.Features.Support(Feature.Updation.Multitable))
{
this.BuildComplex(context, statement, data, member);
}
else
{
this.BuildComplexStandalone(context, statement, data, member);
}
}
}
}
private IEnumerable <JoinClause> Join(Aliaser aliaser, DeleteStatement statement, TableIdentifier table, string fullPath = null)
{
if (table == null || table.Entity == null)
{
yield break;
}
var super = table.Entity.GetBaseEntity();
while (super != null)
{
var clause = JoinClause.Create(table,
fullPath,
name => statement.From.TryGet(name, out var join) ? (JoinClause)join : null,
entity => new TableIdentifier(entity, aliaser.Generate()));
if (!statement.From.Contains(clause))
{
statement.From.Add(clause);
statement.Tables.Add((TableIdentifier)clause.Target);
}
super = super.GetBaseEntity();
yield return(clause);
}
}