src/QueryCat.Backend/Commands/Update/UpdateCommand.cs - develop - krasninja/querycat

src/QueryCat.Backend/Commands/Update/UpdateCommand.cs
58 строк2 KB
Ivan Kozhin
Allow to specify simple expressions in FROM block
24 май 2024, 15:12
24 май 2024, 15:121894842
using QueryCat.Backend.Ast;
using QueryCat.Backend.Ast.Nodes;
using QueryCat.Backend.Ast.Nodes.Select;
using QueryCat.Backend.Ast.Nodes.Update;
using QueryCat.Backend.Commands.Select;
using QueryCat.Backend.Commands.Select.Visitors;
using QueryCat.Backend.Core;
using QueryCat.Backend.Core.Data;
using QueryCat.Backend.Core.Execution;

namespace QueryCat.Backend.Commands.Update;

internal sealed class UpdateCommand : ICommand
{
    /// <inheritdoc />
    public IFuncUnit CreateHandler(IExecutionThread<ExecutionOptions> executionThread, StatementNode node)
    {
        if (executionThread.Options.SafeMode)
        {
            throw new SafeModeException();
        }

        var insertNode = (UpdateNode)node.RootNode;

        // Format SELECT statement and use it for further iterations.
        var selectNode = new SelectQuerySpecificationNode(
            new SelectColumnsListNode(insertNode.SetNodes.Select(n => new SelectColumnsSublistExpressionNode(n.SetTargetNode))
        ));
        selectNode.TableExpressionNode =
            new SelectTableNode(
                    new SelectTableReferenceListNode(insertNode.TargetExpressionNode));
        selectNode.TableExpressionNode.SearchConditionNode = insertNode.SearchConditionNode;
        new SelectPlanner(executionThread).CreateIterator(selectNode);
        var context = selectNode.GetRequiredAttribute<SelectCommandContext>(AstAttributeKeys.ContextKey);

        // Evaluate setters.
        if (context.RowsInputIterator?.RowsInput is not IRowsInputUpdate rowsInput)
        {
            throw new QueryCatException(Resources.Errors.RowsInputNotUpdatable);
        }
        var setters = new List<UpdateSetter>();
        var createDelegateVisitor = new SelectCreateDelegateVisitor(executionThread, context);
        foreach (var setNode in insertNode.SetNodes)
        {
            var columnIndex = rowsInput.GetColumnIndexByName(setNode.SetTargetNode.TableFieldName,
                setNode.SetTargetNode.TableSourceName);
            if (columnIndex < 0)
            {
                throw new QueryCatException(
                    string.Format(Resources.Errors.CannotFindColumn, setNode.SetTargetNode.FullName));
            }
            var func = createDelegateVisitor.RunAndReturn(setNode.SetSourceNode);
            setters.Add(new UpdateSetter(columnIndex, func));
        }

        return new UpdateCommandHandler(context, setters.ToArray());
    }
}