Generating MQL5 Database Entities and Column Metadata with Macros
Summary
The article explains how MQL5 preprocessor macros can reduce repetitive code when building an object-relational mapping layer. It introduces substitutions, parameterized macros, stringification, token concatenation, and passing one macro into another to generate repeated code. It then applies that pattern to database entities: a shared column list can describe each field’s type, name, and default, while separate macros generate class fields, constructor initialization, and string output.
The article also describes extending the same single definition with metadata for table and column properties, including types, primary keys, auto-increment, required status, uniqueness, nullability, and defaults. It presents this as groundwork for later ORM features such as repositories, query building, and automatic table creation. The material is a programming design tutorial, not a trading strategy or performance study; it provides illustrative code patterns but no benchmark or evidence that the approach improves trading results. Macro expansion is text based, so the method depends on careful definitions and does not provide the type checking of ordinary language constructs.
Key ideas
- MQL5 macros can generate repeated declarations and code from a single list of definitions.
- A column list can serve as the shared source for both entity fields and their defaults.
- Additional macros can produce metadata describing database column and table constraints.
- The approach is intended to reduce duplication in an ORM foundation, not to improve trading performance.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.