isimplequery-contract

name	isimplequery-contract
description	The exact iSimpleQuery interface contract that all query drivers must implement. Reference for creating or reviewing drivers.
user-invocable	false

iSimpleQuery Interface Contract

Rules are in .claude/rules/isimplequery-contract.md — this skill provides the interface definition and usage reference.

Interface Definition (SimpleInterface.pas)

iSimpleQuery = interface
  ['{6DCCA942-736D-4C66-AC9B-94151F14853A}']
  function SQL: TStrings;
  function Params: TParams;
  function ExecSQL: iSimpleQuery;
  function DataSet: TDataSet;
  function Open(aSQL: String): iSimpleQuery; overload;
  function Open: iSimpleQuery; overload;
  function StartTransaction: iSimpleQuery;
  function Commit: iSimpleQuery;
  function Rollback: iSimpleQuery;
  function &EndTransaction: iSimpleQuery;
  function InTransaction: Boolean;
  function SQLType: TSQLType;
end;

Method-by-Method Reference

Method	Returns	Purpose
SQL	TStrings	Writable SQL text (DAO writes before Open/ExecSQL)
Params	TParams	Query parameters (DAO writes before Open/ExecSQL)
ExecSQL	Self	Executes INSERT/UPDATE/DELETE
DataSet	TDataSet	Query result after Open
Open(aSQL)	Self	Sets SQL and opens in one call
Open	Self	Opens with SQL already set
StartTransaction	Self	Begins transaction (check InTransaction first)
Commit	Self	Commits active transaction
Rollback	Self	Rolls back active transaction
&EndTransaction	Self	Delegates to Commit
InTransaction	Boolean	True if transaction is active
SQLType	TSQLType	Database type (Firebird, MySQL, SQLite, Oracle)

Constructor Pattern

constructor Create(aConnection: TXxxConnection; aSQLType: TSQLType = TSQLType.Firebird);
class function New(aConnection: TXxxConnection; aSQLType: TSQLType = TSQLType.Firebird): iSimpleQuery;

Existing Drivers

Driver	Connection Type	File
FireDAC	TFDConnection	SimpleQueryFiredac.pas
UniDAC	TUniConnection	SimpleQueryUnidac.pas
Zeos	TZConnection	SimpleQueryZeos.pas
RestDW	TRESTDWClientSQL	SimpleQueryRestDW.pas
Horse (REST)	HTTP URL string	SimpleQueryHorse.pas

How TSimpleDAO Uses iSimpleQuery

1. DAO writes SQL to query.SQL
2. DAO writes params to query.Params
3. For SELECT: calls query.Open then reads query.DataSet
4. For INSERT/UPDATE/DELETE: calls query.ExecSQL
5. Batch operations: query.StartTransaction → operations → query.Commit (or Rollback on error)