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| ///////////////////////////////////////////////////////////////////////////
// //
// Copyright (c) 2015 by Charta Software B.V. //
// All rights reserved //
// //
// Version: 1.7.0.83525 //
// Web site: https://pascal.chartasoftware.com/ //
// //
// This code and information are provided "as is" without warranty of //
// any kind. Dissemination of this information or reproduction of //
// this material is strictly forbidden unless prior written permission //
// is obtained from Charta Software B.V.. //
// //
///////////////////////////////////////////////////////////////////////////
unit Sql.View.Subquery;
interface
uses
Collection.List,
Sql.Database,
Sql.Expression,
Sql.Expression.Row,
Sql.Operator_.Assign,
Sql.Statement.ResultSet,
Sql.Table,
Sql.Table.Column,
Sql.Table.Expression,
Sql.View,
Sql.View.Updater,
Text;
type
ESqlViewNotUpdatable = class(ESqlView);
// Old_TSqlSubqueryView is deprecated because it does not automatically add columns for the columns present in the
// result set statement. Please convert a descendant class by replacing statements like:
//
// Name := CreateColumn(...);
//
// with
//
// Name := Columns[0];
//
Old_TSqlSubqueryView = class(TSqlView)
private
function CreateKeyRestriction(SourceTable: TSqlTable; Restrictions: TList<TSqlExpression>): TSqlExpression;
protected
Updater: TSqlViewUpdater;
function GetOptionalSourceColumn(SourceColumns: TList<TSqlTableColumn>; const Column: TSqlTableColumn): TSqlTableColumn;
function GetSourceColumn(SourceColumns: TList<TSqlTableColumn>; const Column: TSqlTableColumn): TSqlTableColumn;
public
destructor Destroy(); override;
function ToExpression(): TSqlTableExpression; override;
procedure Insert(Database: TSqlDatabase; Columns: TList<TSqlTableColumn>; Rows: TList<TSqlRow>); override;
procedure Update(Database: TSqlDatabase; Assignments: TList<TSqlAssign>; Restrictions: TList<TSqlExpression>); override;
procedure Delete(Database: TSqlDatabase; Restrictions: TList<TSqlExpression>); override;
end deprecated;
TSqlSubqueryView = class(Old_TSqlSubqueryView)
protected
function FindValueForColumn(Column: TSqlTableColumn; Columns: TList<TSqlTableColumn>; Values: TList<TSqlExpression>): TSqlExpression;
public
constructor Create(const Identifier: TText; Statement: TSqlResultSetStatement); override;
end;
implementation
uses
Exception,
Integer._32,
Sql,
Sql.Exception,
Sql.Literal,
Sql.Statement.DataManipulation,
Sql.Statement.ResultSet.Select,
Sql.Table.Column.Reference,
Sql.Table.Expression.ResultSetStatement,
Sql.Table.Index.Column,
Sql.Table.Physical;
{ Old_TSqlSubqueryView }
function Old_TSqlSubqueryView.CreateKeyRestriction(SourceTable: TSqlTable; Restrictions: TList<TSqlExpression>): TSqlExpression;
var
Select: TSqlSelect;
Row: TSqlRow;
KeyColumn: TSqlTableIndexColumn;
begin
Select := TSqlSelect.Create();
Select.From.Add(ToExpression());
Select.Restrictions.AddAll(Restrictions);
if PrimaryKey.Columns.Count > 0 then
begin
Row := TSqlRow.Create();
for KeyColumn in PrimaryKey.Columns do
begin
Row.Columns.Add(TSqlTableColumnReference.Create(GetSourceColumn(SourceTable.Columns, KeyColumn.Column)));
Select.Columns.AddTableColumn(KeyColumn.Column);
end;
Result := InSubquery(Row, Select);
end
else
begin
Select.Columns.AddExpression(TSqlLiteralInteger.Create(1));
Result := Exists(Select);
end;
end;
procedure Old_TSqlSubqueryView.Delete(Database: TSqlDatabase; Restrictions: TList<TSqlExpression>);
var
Statement: TSqlDelete;
begin
if Updater <> nil then
begin
Statement := TSqlDelete.Create();
Statement.TargetTables.Add(Updater.TableToUpdate);
Statement.ReferenceTables.Add(Updater.TableToUpdate.ToExpression());
Statement.Restrictions.Add(CreateKeyRestriction(Updater.TableToUpdate, Restrictions));
Updater.AddFixedValueRestrictions(Statement.Restrictions);
Database.Query(Statement);
end
else
raise ESqlViewNotUpdatable.Create(Identifier);
end;
destructor Old_TSqlSubqueryView.Destroy();
begin
Updater.Free();
inherited Destroy();
end;
function Old_TSqlSubqueryView.GetOptionalSourceColumn(SourceColumns: TList<TSqlTableColumn>; const Column: TSqlTableColumn): TSqlTableColumn;
begin
Result := SourceColumns.Find(TSqlTableColumn.THasIdentifier.Create(Column.Identifier));
end;
function Old_TSqlSubqueryView.GetSourceColumn(SourceColumns: TList<TSqlTableColumn>; const Column: TSqlTableColumn): TSqlTableColumn;
begin
Result := GetOptionalSourceColumn(SourceColumns, Column);
if Result = nil then
raise EException.Create('Cannot find source column: ' + Column.Identifier);
end;
procedure Old_TSqlSubqueryView.Insert(Database: TSqlDatabase; Columns: TList<TSqlTableColumn>; Rows: TList<TSqlRow>);
var
TableToUpdate: TSqlPhysicalTable;
FixedColumnValue: TSqlAssign;
InsertStatement: TSqlInsertValuesStatement;
SourceRow: TSqlRow;
TargetRow: TSqlRow;
Column: TSqlTableColumn;
SourceColumn: TSqlTableColumn;
Value: TSqlExpression;
Index: TInteger32;
begin
if Updater <> nil then
begin
TableToUpdate := Updater.TableToUpdate;
InsertStatement := TSqlInsertValues.Create(TableToUpdate);
for Column in Columns do
begin
SourceColumn := GetOptionalSourceColumn(TableToUpdate.Columns, Column);
if SourceColumn <> nil then
InsertStatement.Columns.Add(SourceColumn);
end;
for FixedColumnValue in Updater.FixedValueColumns do
InsertStatement.Columns.Add(GetSourceColumn(TableToUpdate.Columns, FixedColumnValue.Column));
for SourceRow in Rows do
begin
TargetRow := TSqlRow.Create();
for Index := 0 to Columns.Count - 1 do
begin
Column := Columns[Index];
Value := SourceRow.Columns[Index];
SourceColumn := GetOptionalSourceColumn(TableToUpdate.Columns, Column);
if SourceColumn <> nil then
TargetRow.Columns.Add(Value)
else if not (Value is TSqlExpression) then
raise ESql.Create('Cannot specify value for column: ' + Column.Identifier);
end;
for FixedColumnValue in Updater.FixedValueColumns do
TargetRow.Columns.Add(FixedColumnValue.Value);
InsertStatement.Rows.Add(TargetRow);
end;
Database.Query(InsertStatement);
end
else
raise ESqlViewNotUpdatable.Create(Identifier);
end;
function Old_TSqlSubqueryView.ToExpression(): TSqlTableExpression;
begin
Result := TSqlResultSetStatementTableExpression.Create(Statement, Identifier);
end;
procedure Old_TSqlSubqueryView.Update(Database: TSqlDatabase; Assignments: TList<TSqlAssign>; Restrictions: TList<TSqlExpression>);
var
Update: TSqlUpdate;
Assignment: TSqlAssign;
begin
if Updater <> nil then
begin
Update := TSqlUpdate.Create();
Update.Tables.Add(Updater.TableToUpdate.ToExpression());
for Assignment in Assignments do
Update.Assignments.Add(Assign(GetSourceColumn(Updater.UpdatableColumns, Assignment.Column), Assignment.Value));
Updater.AddFixedValueRestrictions(Update.Restrictions);
Update.Restrictions.Add(CreateKeyRestriction(Updater.TableToUpdate, Restrictions));
Database.Query(Update);
end
else
raise ESqlViewNotUpdatable.Create(Identifier);
end;
{ TSqlSubqueryView }
constructor TSqlSubqueryView.Create(const Identifier: TText; Statement: TSqlResultSetStatement);
var
ResultSetColumn: TSqlResultSetColumn;
TableColumn: TSqlTableColumn;
begin
inherited Create(Identifier, Statement);
for ResultSetColumn in Statement.Columns do
begin
TableColumn := CreateColumn(ResultSetColumn);
if TableColumn.Identifier.Count = 0 then
raise EException.Create(ClassName + ' does not support queries without column identifiers!');
end;
end;
function TSqlSubqueryView.FindValueForColumn(Column: TSqlTableColumn; Columns: TList<TSqlTableColumn>; Values: TList<TSqlExpression>): TSqlExpression;
var
i: TInteger32;
begin
Result := nil;
i := 0;
while (Result = nil) and (i < Columns.Count) do
begin
if Column.Identifier = Columns[i].Identifier then
Result := Values[i]
else
Inc(i);
end;
if Result = nil then
raise EException.Create('Cannot find value for column ' + Column.Identifier);
end;
end.
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