/// <summary>
/// 创建 SQL 命令
/// </summary>
/// <param name="dbQueryable">查询 语句</param>
/// <param name="indent">缩进</param>
/// <param name="isOuter">是否最外层，内层查询不需要结束符(;)</param>
/// <param name="parameters">已存在的参数列表</param>
/// <returns></returns>
public DbCommandDefinition Resolve <T>(IDbQueryable <T> dbQueryable, int indent = 0, bool isOuter = true, List <IDbDataParameter> parameters = null)
{
// 设置该查询是否需要参数化
if (!((DbQueryable)dbQueryable).HasSetParameterized)
{
dbQueryable.Parameterized = true;
}
if (dbQueryable.Parameterized && parameters == null)
{
parameters = new List <IDbDataParameter>(8);
}
// 解析查询语义
IDbQueryableInfo <T> info = DbQueryParser.Parse(dbQueryable);
DbQueryableInfo_Select <T> sQuery = info as DbQueryableInfo_Select <T>;
if (sQuery != null)
{
return(this.ParseSelectCommand <T>(sQuery, indent, isOuter, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Insert <T> nQuery = info as DbQueryableInfo_Insert <T>;
if (nQuery != null)
{
return(this.ParseInsertCommand <T>(nQuery, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Update <T> uQuery = info as DbQueryableInfo_Update <T>;
if (uQuery != null)
{
return(this.ParseUpdateCommand <T>(uQuery, dbQueryable.Parameterized ? parameters : null));
}
DbQueryableInfo_Delete <T> dQuery = info as DbQueryableInfo_Delete <T>;
if (dQuery != null)
{
return(this.ParseDeleteCommand <T>(dQuery, dbQueryable.Parameterized ? parameters : null));
}
throw new NotImplementedException();
}
// 获取 JOIN 子句关联表的的别名
protected TableAliasCache PrepareAlias <T>(DbQueryableInfo_Select <T> query)
{
TableAliasCache aliases = new TableAliasCache((query.Join != null ? query.Join.Count : 0) + 1);
foreach (DbExpression exp in query.Join)
{
// [INNER/LEFT JOIN]
if (exp.DbExpressionType == DbExpressionType.GroupJoin || exp.DbExpressionType == DbExpressionType.Join || exp.DbExpressionType == DbExpressionType.GroupRightJoin)
{
this.PrepareLfInJoinAlias(exp, aliases);
}
else if (exp.DbExpressionType == DbExpressionType.SelectMany)
{
this.PrepareCrossJoinAlias(exp, aliases);
}
}
return(aliases);
}
// 构造由一对多关系产生的嵌套查询
static DbQueryableInfo_Select <TElement> TryBuilOuter <TElement>(DbQueryableInfo_Select <TElement> sQuery)
{
if (sQuery == null || sQuery.Select == null)
{
return(sQuery);
}
Expression select = sQuery.Select.Expressions[0];
List <DbExpression> include = sQuery.Include;
Type type = sQuery.FromType;
// 解析导航属性 如果有 一对多 的导航属性，那么查询的结果集的主记录将会有重复记录，这时就需要使用嵌套语义，先查主记录，再关联导航记录
bool checkListNavgation = false;
Expression expression = select;
LambdaExpression lambdaExpression = expression as LambdaExpression;
if (lambdaExpression != null)
{
expression = lambdaExpression.Body;
}
MemberInitExpression initExpression = expression as MemberInitExpression;
NewExpression newExpression = expression as NewExpression;
foreach (DbExpression d in include)
{
Expression exp = d.Expressions[0];
if (exp.NodeType == ExpressionType.Lambda)
{
exp = (exp as LambdaExpression).Body;
}
else if (exp.NodeType == ExpressionType.Call)
{
exp = (exp as MethodCallExpression).Object;
}
// Include 如果包含List<>泛型导航，则可以判定整个查询包含一对多的导航
//if (exp.Type.IsGenericType && exp.Type.GetGenericTypeDefinition() == typeof(List<>)) checkListNavgation = true;
if (TypeUtils.IsCollectionType(exp.Type))
{
checkListNavgation = true;
}
if (checkListNavgation)
{
break;
}
}
if (!checkListNavgation)
{
checkListNavgation = initExpression != null && CheckListNavigation <TElement>(initExpression);
}
if (checkListNavgation)
{
newExpression = initExpression != null ? initExpression.NewExpression : newExpression;
List <MemberBinding> bindings = new List <MemberBinding>();
if (initExpression != null)
{
bindings = initExpression.Bindings.ToList(x => x, x => TypeUtils.IsPrimitiveType((x.Member as System.Reflection.PropertyInfo).PropertyType));
}
if (newExpression != null || bindings.Count() > 0)
{
// 简化内层选择器，只选择最小字段，不选择导航字段，导航字段在外层加进去
initExpression = Expression.MemberInit(newExpression, bindings);
lambdaExpression = Expression.Lambda(initExpression, lambdaExpression.Parameters);
sQuery.Select = new DbExpression(DbExpressionType.Select, lambdaExpression);
}
sQuery.GenByListNavigation = true;
sQuery.Include = new List <DbExpression>();
var outQuery = new DbQueryableInfo_Select <TElement>();
outQuery.FromType = type;
outQuery.SubQueryInfo = sQuery;
outQuery.Join = new List <DbExpression>();
outQuery.OrderBy = new List <DbExpression>();
outQuery.Include = include;
outQuery.HaveListNavigation = true;
outQuery.Select = new DbExpression(DbExpressionType.Select, select);
if (sQuery.GroupBy != null)
{
// 查看外层是否需要重新构造选择器。如果有分组并且有聚合函数，则需要重新构造选择器。否则外层解析不了聚合函数
// demo=> line 640
bool newSelector = bindings.Any(x => ((MemberAssignment)x).Expression.NodeType == ExpressionType.Call) ||
newExpression.Arguments.Any(x => x.NodeType == ExpressionType.Call);
if (newSelector)
{
// 1对多导航嵌套查询外层的的第一个表别名固定t0，参数名可随意
ParameterExpression p = Expression.Parameter(newExpression.Type, "__g");
bindings = bindings.ToList(x => (MemberBinding)Expression.Bind(x.Member, Expression.MakeMemberAccess(p, x.Member)));
List <Expression> arguments = null;
if (newExpression.Members != null)
{
arguments = new List <Expression>(newExpression.Arguments.Count);
for (int i = 0; i < newExpression.Arguments.Count; i++)
{
var member = newExpression.Members[i];
var arg = Expression.MakeMemberAccess(p, member);
arguments.Add(arg);
}
}
newExpression = Expression.New(newExpression.Constructor, arguments, newExpression.Members);
initExpression = Expression.MemberInit(newExpression, bindings);
lambdaExpression = Expression.Lambda(initExpression, lambdaExpression.Parameters);
outQuery.Select = new DbExpression(DbExpressionType.Select, lambdaExpression);
}
}
sQuery = outQuery;
}
else if (sQuery.Union.Count > 0 && (sQuery.Take > 0 || sQuery.Skip > 0))
{
var outQuery = new DbQueryableInfo_Select <TElement>();
outQuery.FromType = type;
outQuery.Select = new DbExpression(DbExpressionType.Select, select);
outQuery.SubQueryInfo = sQuery;
outQuery.Skip = sQuery.Skip;
outQuery.Take = sQuery.Take;
outQuery.Join = new List <DbExpression>();
outQuery.OrderBy = new List <DbExpression>();
outQuery.OrderBy.AddRange(sQuery.OrderBy);
sQuery.OrderBy = new List <DbExpression>();
sQuery.Skip = 0;
sQuery.Take = 0;
sQuery = outQuery;
}
return(sQuery);
}
// 创建 SELECT 命令 protected abstract DbCommandDefinition ParseSelectCommand <T>(DbQueryableInfo_Select <T> sQuery, int indent = 0, bool isOuter = true, List <IDbDataParameter> parameters = null);
// 解析查询语义
static IDbQueryableInfo <TElement> Parse <TElement>(IDbQueryable <TElement> dbQuery, int startIndex)
{
// 目的：将query 转换成增/删/改/查
// 1、from a in context.GetTable<T>() select a 此时query里面可能没有SELECT 表达式
// 2、Take 视为一个查询的结束位，如有更多查询，应使用嵌套查询
// 3、Uion 分页查询也使嵌套语义
Type type = null;
bool isDistinct = false;
bool isAny = false;
bool isSubQuery = false;
int? skip = null;
int? take = null;
int? outerIndex = null;
List <Expression> where = new List <Expression>(); // WHERE
List <Expression> having = new List <Expression>(); // HAVING
List <DbExpression> join = new List <DbExpression>(); // JOIN
List <DbExpression> orderBy = new List <DbExpression>(); // ORDER BY
List <DbExpression> include = new List <DbExpression>(); // ORDER BY
List <IDbQueryableInfo <TElement> > union = new List <IDbQueryableInfo <TElement> >();
Expression select = null; // SELECT #
DbExpression insert = null; // INSERT #
DbExpression update = null; // UPDATE #
DbExpression delete = null; // DELETE #
DbExpression groupBy = null; // GROUP BY #
DbExpression statis = null; // SUM/MAX #
for (int index = startIndex; index < dbQuery.DbExpressions.Count; ++index)
{
DbExpression curExp = dbQuery.DbExpressions[index];
// Take(n)
if (take != null || (skip != null && curExp.DbExpressionType != DbExpressionType.Take) || isDistinct || isSubQuery)
{
outerIndex = index;
break;
}
#region 分析语义
switch (curExp.DbExpressionType)
{
case DbExpressionType.None:
case DbExpressionType.All:
continue;
case DbExpressionType.Any:
isAny = true;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
break;
case DbExpressionType.AsSubQuery:
isSubQuery = true;
//if (curExp.Expressions != null) where.Add(curExp.Expressions[0]);
break;
case DbExpressionType.Union:
var uQuery = (curExp.Expressions[0] as ConstantExpression).Value as IDbQueryable <TElement>;
var u = DbQueryParser.Parse(uQuery);
union.Add(u);
continue;
case DbExpressionType.Include:
include.Add(curExp);
continue;
case DbExpressionType.GroupBy:
groupBy = curExp;
continue;
case DbExpressionType.GetTable:
type = (curExp.Expressions[0] as ConstantExpression).Value as Type;
continue;
case DbExpressionType.Average:
case DbExpressionType.Min:
case DbExpressionType.Sum:
case DbExpressionType.Max:
statis = curExp;
continue;
case DbExpressionType.Count:
statis = curExp;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Distinct:
isDistinct = true;
continue;
case DbExpressionType.First:
case DbExpressionType.FirstOrDefault:
take = 1;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Join:
case DbExpressionType.GroupJoin:
case DbExpressionType.GroupRightJoin:
select = curExp.Expressions[3];
join.Add(curExp);
continue;
case DbExpressionType.OrderBy:
case DbExpressionType.OrderByDescending:
orderBy.Add(curExp);
continue;
case DbExpressionType.Select:
select = curExp.Expressions != null ? curExp.Expressions[0] : null;
continue;
case DbExpressionType.SelectMany:
select = curExp.Expressions[1];
if (CheckSelectMany(dbQuery.DbExpressions, curExp, startIndex))
{
join.Add(curExp);
}
continue;
case DbExpressionType.Single:
case DbExpressionType.SingleOrDefault:
take = 1;
if (curExp.Expressions != null)
{
where.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Skip:
skip = (int)(curExp.Expressions[0] as ConstantExpression).Value;
continue;
case DbExpressionType.Take:
take = (int)(curExp.Expressions[0] as ConstantExpression).Value;
continue;
case DbExpressionType.ThenBy:
case DbExpressionType.ThenByDescending:
orderBy.Add(curExp);
continue;
case DbExpressionType.Where:
var predicate = groupBy == null ? where : having;
if (curExp.Expressions != null)
{
predicate.Add(curExp.Expressions[0]);
}
continue;
case DbExpressionType.Insert:
insert = curExp;
continue;
case DbExpressionType.Update:
update = curExp;
continue;
case DbExpressionType.Delete:
delete = curExp;
continue;
default:
throw new NotSupportedException(string.Format("{0} is not support.", curExp.DbExpressionType));
}
#endregion
}
// 没有解析到INSERT/DELETE/UPDATE/SELECT表达式，并且没有相关统计函数，则默认选择FromType的所有字段
bool useFullColumns = insert == null && delete == null && update == null && select == null && statis == null;
if (useFullColumns)
{
select = Expression.Constant(type ?? typeof(TElement));
}
var sQuery = new DbQueryableInfo_Select <TElement>();
sQuery.FromType = type;
sQuery.HaveDistinct = isDistinct;
sQuery.HaveAny = isAny;
sQuery.Join = join;
sQuery.OrderBy = orderBy;
sQuery.GroupBy = groupBy;
sQuery.Statis = statis;
sQuery.Union = union;
sQuery.Include = include;
sQuery.Skip = skip != null ? skip.Value : 0;
sQuery.Take = take != null ? take.Value : 0;
sQuery.Select = new DbExpression(DbExpressionType.Select, select);
sQuery.Where = new DbExpression(DbExpressionType.Where, DbQueryParser.CombineWhere(where));
sQuery.Having = new DbExpression(DbExpressionType.None, DbQueryParser.CombineWhere(having));
sQuery.SourceQuery = dbQuery;
// 更新
if (update != null)
{
var uQuery = new DbQueryableInfo_Update <TElement>();
ConstantExpression expression2 = update.Expressions != null ? update.Expressions[0] as ConstantExpression : null;
if (expression2 != null)
{
uQuery.Entity = expression2.Value;
}
else
{
uQuery.Expression = update.Expressions[0];
}
uQuery.SelectInfo = sQuery;
uQuery.SourceQuery = dbQuery;
return(uQuery);
}
// 删除
if (delete != null)
{
var dQuery = new DbQueryableInfo_Delete <TElement>();
ConstantExpression expression2 = delete.Expressions != null ? delete.Expressions[0] as ConstantExpression : null;
if (expression2 != null)
{
dQuery.Entity = expression2.Value;
}
dQuery.SelectInfo = sQuery;
dQuery.SourceQuery = dbQuery;
return(dQuery);
}
// 新增
if (insert != null)
{
var nQuery = new DbQueryableInfo_Insert <TElement>();
if (insert.Expressions != null)
{
nQuery.Entity = (insert.Expressions[0] as ConstantExpression).Value;
if (insert.Expressions.Length > 1)
{
nQuery.EntityColumns = (insert.Expressions[1] as ConstantExpression).Value as IList <Expression>;
}
}
nQuery.SelectInfo = sQuery;
nQuery.Bulk = dbQuery.Bulk;
nQuery.SourceQuery = dbQuery;
dbQuery.DbQueryInfo = nQuery;
return(nQuery);
}
// 如果有一对多的导航关系，则产生嵌套语义的查询
if (select != null)
{
// 如果有uion但是没分页，应去掉orderby子句
if (sQuery.Union.Count > 0 && !(sQuery.Take > 0 || sQuery.Skip > 0))
{
sQuery.OrderBy = new List <DbExpression>();
}
// 检查嵌套查询语义
sQuery = DbQueryParser.TryBuilOuter(sQuery);
sQuery.SourceQuery = dbQuery;
}
// 解析嵌套查询
if (outerIndex != null)
{
var outQuery = DbQueryParser.Parse <TElement>(dbQuery, outerIndex.Value);
var nQuery = outQuery as DbQueryableInfo_Insert <TElement>;
var uQuery = outQuery as DbQueryableInfo_Update <TElement>;
if (nQuery != null)
{
if (nQuery.SelectInfo != null)
{
nQuery.SelectInfo.SubQueryInfo = sQuery;
}
else
{
nQuery.SelectInfo = sQuery;
}
nQuery.SourceQuery = dbQuery;
return(nQuery);
}
else if (uQuery != null)
{
if (uQuery.SelectInfo != null)
{
uQuery.SelectInfo.SubQueryInfo = sQuery;
}
else
{
uQuery.SelectInfo = sQuery;
}
uQuery.SourceQuery = dbQuery;
return(uQuery);
}
else
{
outQuery.SubQueryInfo = sQuery;
outQuery.SourceQuery = dbQuery;
return(outQuery);
}
}
// 查询表达式
return(sQuery);
}
