/// <summary>
/// 使用临时表形式，生成插入单个数据对象语句，对象的主键是标识列，
/// 要求数据库拥有<see cref="EDbCapable.TemporaryTable"/>
/// 和<see cref="EDbCapable.ModifyJoin"/>两个特性。
/// </summary>
/// <param name="context">生成上下文。</param>
/// <returns>语句片段。</returns>
protected virtual SqlFragment GenerateForInsertIdentityTempTable(GenerateContext context)
{
var data = (GenerateDataForInsert)context.Data;
var mainunit = (CommitIdentityUnit)data.MainUnit;
var members = data.GetTables().SelectMany(a => a.Members).ToList();
var rowindex = new ColumnMetadata(data.Table, SupportMembers.DbMembers.CustomRowIndex,
members.Select(a => a.Name).Unique("RowIndex"));
members.Add(rowindex);
var createtable = new CreateTempTableFragment(context, members);
var temptable = createtable.Table;
var insert = new InsertValueFragment(context, temptable, data.CommitObject, data.Items);
data.CommitObject.Parent = insert;
foreach (var unit in data.GetUnits())
{
unit.Members.ForEach(member => GenerateForInsertMembers(insert, member));
}
insert.SetValue(mainunit.Identity.Metadata, new SimpleFragment(context, "0"));
var rowindexfragment = new RowIndexFragment(context);
insert.SetValue(rowindex, rowindexfragment);
TableFragment whileTarget = null;
BlockFragment block = null;
if (context.Feature.HasCapable(EDbCapable.ExternalCompoundStatement))
{
var index = new CreateVariableFragment(context, typeof(int));
var whilefragment = GenerateForInsertIdentityMultipleWhile(context, mainunit, index,
rowindex, createtable.Table, rowindexfragment, out whileTarget);
block = new BlockFragment(context, index, createtable, insert,
context.Assign(index.Name, context.StatementString("1")), whilefragment);
}
else
{
var repeatfragment = GenerateForInsertIdentityMultipleRepeat(context, mainunit,
rowindex, createtable.Table, rowindexfragment, data, out whileTarget);
block = new BlockFragment(context, createtable, insert, repeatfragment);
}
if (data.SubUnits != null)
{
foreach (var unit in data.SubUnits)
{
block.Add(context.Insert(createtable.Table, unit));
}
}
GenerateForInsertReturnStatement(context, block, whileTarget, createtable.Table);
return(block);
}
private WhileFragment GenerateForInsertIdentityMultipleWhile(GenerateContext context, CommitIdentityUnit mainunit, CreateVariableFragment index,
ColumnMetadata rowindex, TemporaryTableFragment temporaryTable, RowIndexFragment rowindexfragment, out TableFragment whileTarget)
{
var whilefragment = new WhileFragment(context, context.LessThan(index.Name, rowindexfragment));
var block = whilefragment.Block;
var whileInsert = context.Insert(temporaryTable, mainunit.Table,
mainunit.Members.Where(a => a.ValueType != ECommitValueType.Database).Select(a => a.Metadata));
var whileSelect = (QueryBaseFragment)whileInsert.Query;
whileSelect.Where = context.Equal(temporaryTable.GetMember(rowindex), index.Name);
block.Add(whileInsert);
var whileUpdate = new UpdateFragment(context, temporaryTable);
var getidentity = whileUpdate.CreateExpression(
context.Translate(Expression.Call(null, SupportMembers.DbFunctions.GetIdentity)));
whileUpdate.SetValue(mainunit.Identity.Metadata, getidentity);
whileUpdate.Where = context.Equal(temporaryTable.GetMember(rowindex), index.Name);
block.Add(whileUpdate);
block.Add(context.Assign(index.Name, context.Add(index.Name, context.StatementString("1"))));
whileTarget = (TableFragment)whileInsert.Target;
return(whilefragment);
}