Creates, changes or deletes rows in any CIVIL NX database table through the MIDAS API — nodes, elements, materials, sections, thicknesses, supports, links, load cases, loads, groups, stages, combinations, anything the API manual lists — so a model can be built from scratch or changed where no plugin tool does it. Look up the table and its fields first with midas_docs_search / midas_docs_read (e.g. "db/ELEM"), and read the current rows with civil_read_table. writes is a list of steps run in order: { table, op: create (POST — new keys only, refused if a key exists) | upsert (PUT — creates or changes; GRUP lists and CNLD/BMLD/PRES/RIGD items MERGE, they are never removed by a PUT) | delete (DESTRUCTIVE — needs allowDestructive; a node takes its elements, an element its loads, a load case its loads), rows: { "<key>": {fields} } | ids: [keys] }. The preview simulates every step over the current model: what each creates, changes (which fields) and deletes; it blocks keys that already exist on create, elements that refer to nodes, materials, sections or thicknesses that do not exist (CIVIL NX accepts a missing section silently), deletes and UNIT / MVCD writes without allowDestructive. Then apply: true with confirmPlanHash writes the steps (stopping at the first refusal), reads every touched row back and reports anything not stored as sent. civil_write_tables_undo puts every touched row back.
