// 创建 DELETE 命令
protected override Command ResolveDeleteCommand <T>(DbQueryableInfo_Delete <T> dbQuery, ResolveToken token)
{
ISqlBuilder builder = this.CreateSqlBuilder(token);
TypeRuntimeInfo typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo <T>();
builder.Append("DELETE FROM ");
builder.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);
builder.Append(" ");
if (dbQuery.Entity != null)
{
if (typeRuntime.KeyInvokers == null || typeRuntime.KeyInvokers.Count == 0)
{
throw new XFrameworkException("Delete<T>(T value) require entity must have key column.");
}
object entity = dbQuery.Entity;
builder.AppendNewLine();
builder.Append("WHERE ");
foreach (var invoker in typeRuntime.KeyInvokers)
{
var column = invoker.Column;
var value = invoker.Invoke(entity);
var seg = this.DbValue.GetSqlValue(value, token, column);
builder.AppendMember(invoker.Member.Name);
builder.Append(" = ");
builder.Append(seg);
builder.Append(" AND ");
}
builder.Length -= 5;
}
else if (dbQuery.SelectInfo != null)
{
LambdaExpression lambda = null;
var sourceQuery = dbQuery.SourceQuery;
if (sourceQuery.DbExpressions != null && sourceQuery.DbExpressions.Count > 1)
{
switch (sourceQuery.DbExpressions[1].DbExpressionType)
{
case DbExpressionType.Join:
case DbExpressionType.GroupJoin:
case DbExpressionType.GroupRightJoin:
lambda = (LambdaExpression)sourceQuery.DbExpressions[1].Expressions[1];
break;
case DbExpressionType.Select:
case DbExpressionType.SelectMany:
lambda = (LambdaExpression)sourceQuery.DbExpressions[1].Expressions[0];
break;
}
}
if (lambda == null)
{
DbExpression dbExpression = dbQuery.SelectInfo.Select;
dbExpression = dbQuery.SelectInfo.Condtion;
if (dbExpression != null && dbExpression.Expressions != null)
{
lambda = (LambdaExpression)dbExpression.Expressions[0];
}
}
// 解析查询以确定是否需要嵌套
var parameter = Expression.Parameter(typeof(SQLiteRowId), lambda != null ? lambda.Parameters[0].Name : "x");
var expression = Expression.MakeMemberAccess(parameter, (_rowIdExpression.Body as MemberExpression).Member);
dbQuery.SelectInfo.Select = new DbExpression(DbExpressionType.Select, expression);
var cmd = (MapperCommand)this.ResolveSelectCommand <T>(dbQuery.SelectInfo, 1, false, null);
if (token != null && token.Extendsions == null)
{
token.Extendsions = new Dictionary <string, object>();
if (!token.Extendsions.ContainsKey("SQLiteDelete"))
{
token.Extendsions.Add("SQLiteDelete", null);
}
}
if ((cmd.NavMembers != null && cmd.NavMembers.Count > 0) || dbQuery.SelectInfo.Joins.Count > 0)
{
cmd = (MapperCommand)this.ResolveSelectCommand <T>(dbQuery.SelectInfo, 1, false, token);
builder.Append("WHERE ");
builder.AppendMember("RowID");
builder.Append(" IN(");
builder.AppendNewLine(cmd.CommandText);
builder.Append(')');
}
else
{
TableAliasCache aliases = this.PrepareTableAlias <T>(dbQuery.SelectInfo, token);
ExpressionVisitorBase visitor = null;
visitor = new JoinExpressionVisitor(this, aliases, dbQuery.SelectInfo.Joins);
visitor.Write(builder);
visitor = new WhereExpressionVisitor(this, null, dbQuery.SelectInfo.Condtion);
visitor.Write(builder);
}
}
builder.Append(';');
return(new Command(builder.ToString(), builder.Token != null ? builder.Token.Parameters : null, System.Data.CommandType.Text));
}
// 创建 SELECT 命令
Command ResolveSelectCommandImpl <T>(DbQueryableInfo_Select <T> dbQuery, int indent, bool isOuter, ResolveToken token)
{
// 说明：
// 1.OFFSET 前必须要有 'ORDER BY'，即 'Skip' 子句前必须使用 'OrderBy' 子句
// 2.在有聚合函数的<MAX,MIN...>情况下，如果有 'Distinct' 'GroupBy' 'Skip' 'Take' 子句，则需要使用嵌套查询
// 3.'Any' 子句将翻译成 IF EXISTS...
// 4.分组再分页时需要使用嵌套查询，此时子查询不需要 'OrderBy' 子句，但最外层则需要
// 5.'Skip' 'Take' 子句视为语义结束符，在其之后的子句将使用嵌套查询
// 6.导航属性中有 1:n 关系的，需要使用嵌套查询，否则分页查询会有问题
// 导航属性中有1:n关系，只统计主表
// 例：AccountList = a.Client.AccountList,
var subQuery = dbQuery.SubQueryInfo as DbQueryableInfo_Select <T>;
if (dbQuery.HasMany && subQuery != null && subQuery.Aggregate != null)
{
dbQuery = subQuery;
}
bool useStatis = dbQuery.Aggregate != null;
bool useNesting = dbQuery.HasDistinct || dbQuery.GroupBy != null || dbQuery.Skip > 0 || dbQuery.Take > 0;
string alias0 = token != null && !string.IsNullOrEmpty(token.TableAliasName) ? (token.TableAliasName + "0") : "t0";
// 没有聚合函数或者使用 'Skip' 子句，则解析OrderBy
// 导航属性如果使用嵌套，除非有 TOP 或者 OFFSET 子句，否则不能用ORDER BY
bool useOrderBy = (!useStatis || dbQuery.Skip > 0) && !dbQuery.HasAny && (!dbQuery.SubQueryOfMany || (dbQuery.Skip > 0 || dbQuery.Take > 0));
TableAliasCache aliases = this.PrepareTableAlias <T>(dbQuery, token);
MapperCommand cmd = new MapperCommand(this, aliases, token)
{
HasMany = dbQuery.HasMany
};
ISqlBuilder jf = cmd.JoinFragment;
ISqlBuilder wf = cmd.WhereFragment;
jf.Indent = indent;
#region 嵌套查询
if (useStatis && useNesting)
{
// SELECT
jf.Append("SELECT ");
jf.AppendNewLine();
// SELECT COUNT(1)
var visitor2 = new AggregateExpressionVisitor(this, aliases, dbQuery.Aggregate, dbQuery.GroupBy, alias0);
visitor2.Write(jf);
cmd.AddNavMembers(visitor2.NavMembers);
// SELECT COUNT(1) FROM
jf.AppendNewLine();
jf.Append("FROM ( ");
indent += 1;
jf.Indent = indent;
}
#endregion
#region 择子句
// SELECT 子句
if (jf.Indent > 0)
{
jf.AppendNewLine();
}
jf.Append("SELECT ");
if (dbQuery.HasAny)
{
jf.Append("CASE WHEN COUNT(1) = 1 THEN 1 ELSE 0 END FROM (");
indent += 1;
jf.Indent = indent;
jf.AppendNewLine();
jf.Append("SELECT 1 ");
}
if (useStatis && !useNesting)
{
// 如果有聚合函数，并且不是嵌套的话，则直接使用SELECT <MAX,MIN...>，不需要解析选择的字段
jf.AppendNewLine();
var visitor2 = new AggregateExpressionVisitor(this, aliases, dbQuery.Aggregate, dbQuery.GroupBy);
visitor2.Write(jf);
cmd.AddNavMembers(visitor2.NavMembers);
}
else
{
// DISTINCT 子句
if (dbQuery.HasDistinct)
{
jf.Append("DISTINCT ");
}
#region 择字段
if (!dbQuery.HasAny)
{
// SELECT 范围
var visitor2 = new ColumnExpressionVisitor(this, aliases, dbQuery);
visitor2.Write(jf);
cmd.PickColumns = visitor2.PickColumns;
cmd.PickColumnText = visitor2.PickColumnText;
cmd.Navigations = visitor2.Navigations;
cmd.AddNavMembers(visitor2.NavMembers);
}
#endregion
}
#endregion
#region 顺序解析
// FROM 子句
jf.AppendNewLine();
jf.Append("FROM ");
if (dbQuery.SubQueryInfo != null)
{
// 子查询
jf.Append('(');
Command cmd2 = this.ResolveSelectCommandImpl <T>(dbQuery.SubQueryInfo as DbQueryableInfo_Select <T>, indent + 1, false, token);
jf.Append(cmd2.CommandText);
jf.AppendNewLine();
jf.Append(") ");
jf.Append(alias0);
jf.Append(' ');
}
else
{
var typeRuntime = TypeRuntimeInfoCache.GetRuntimeInfo(dbQuery.FromEntityType);
jf.AppendMember(typeRuntime.TableName, !typeRuntime.IsTemporary);
jf.Append(' ');
jf.Append(alias0);
jf.Append(' ');
}
// LEFT<INNER> JOIN 子句
ExpressionVisitorBase visitor = new JoinExpressionVisitor(this, aliases, dbQuery.Joins);
visitor.Write(jf);
wf.Indent = jf.Indent;
// WHERE 子句
visitor = new WhereExpressionVisitor(this, aliases, dbQuery.Condtion);
visitor.Write(wf);
cmd.AddNavMembers(visitor.NavMembers);
// GROUP BY 子句
visitor = new GroupByExpressionVisitor(this, aliases, dbQuery.GroupBy);
visitor.Write(wf);
cmd.AddNavMembers(visitor.NavMembers);
// HAVING 子句
visitor = new HavingExpressionVisitor(this, aliases, dbQuery.Having, dbQuery.GroupBy);
visitor.Write(wf);
cmd.AddNavMembers(visitor.NavMembers);
// ORDER 子句
if (dbQuery.OrderBys.Count > 0 && useOrderBy)
{
visitor = new OrderByExpressionVisitor(this, aliases, dbQuery.OrderBys, dbQuery.GroupBy);
visitor.Write(wf);
cmd.AddNavMembers(visitor.NavMembers);
}
#endregion
#region 分页查询
if (dbQuery.Take > 0)
{
wf.AppendNewLine().AppendFormat("LIMIT {0}", this.DbValue.GetSqlValue(dbQuery.Take, token));
}
else if (dbQuery.Take == 0 && dbQuery.Skip > 0)
{
wf.AppendNewLine().AppendFormat("LIMIT {0}", this.DbValue.GetSqlValue(-1, token));
}
if (dbQuery.Skip > 0)
{
wf.AppendFormat(" OFFSET {0}", this.DbValue.GetSqlValue(dbQuery.Skip, token));
}
#endregion
#region 嵌套查询
if (useStatis && useNesting)
{
cmd.CombineFragments();
indent -= 1;
jf.Indent = indent;
jf.AppendNewLine();
jf.Append(") ");
jf.Append(alias0);
}
#endregion
#region 嵌套导航
// TODO Include 从表，没分页，OrderBy 报错
if (dbQuery.HasMany && subQuery != null && subQuery.OrderBys.Count > 0 && subQuery.Aggregate == null && !(subQuery.Skip > 0 || subQuery.Take > 0))
{
cmd.CombineFragments();
visitor = new OrderByExpressionVisitor(this, aliases, subQuery.OrderBys);//, null, "t0");
visitor.Write(jf);
}
#endregion
#region 并集查询
// UNION 子句
if (dbQuery.Unions != null && dbQuery.Unions.Count > 0)
{
cmd.CombineFragments();
for (int index = 0; index < dbQuery.Unions.Count; index++)
{
jf.AppendNewLine();
jf.Append("UNION ALL");
if (indent == 0)
{
jf.AppendNewLine();
}
Command cmd2 = this.ResolveSelectCommand <T>(dbQuery.Unions[index] as DbQueryableInfo_Select <T>, indent, isOuter, token);
jf.Append(cmd2.CommandText);
}
}
#endregion
#region Any 子句
// 'Any' 子句
if (dbQuery.HasAny)
{
// 产生 WHERE 子句
cmd.CombineFragments();
// 如果没有分页，则显式指定只查一笔记录
if (dbQuery.Take == 0 && dbQuery.Skip == 0)
{
jf.AppendNewLine();
jf.Append("LIMIT 1");
}
indent -= 1;
jf.Indent = indent;
jf.AppendNewLine();
jf.Append(") ");
jf.Append(alias0);
}
#endregion
return(cmd);
}