Record the SQL dialect, the newline-in-a-column shape, the fixed column set and the string view's divergence
Tests / vet + fmt + tests (pull_request) Successful in 1m1s

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2026-09-04 08:43:12 +02:00
parent 8cb8cf6334
commit 7ee7f1788b
2 changed files with 43 additions and 9 deletions
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@@ -11,6 +11,13 @@
# Deferred # Deferred
- **A record cannot ask for an independent reference draw (2026-09-04).** Within
one record every tailed reference to a category is one draw, and a bare
`{/cat}` renders the whole category, so a column wanting its own draw of
`{/cat.field}` has no spelling for it. Left until a use case names which columns
should disagree; premise: a record is one coherent row, which is what columns
are for. Not raised in review before that.
- **Shipped-data de-duplication (2026-09-02).** `email.json`'s `local` is a - **Shipped-data de-duplication (2026-09-02).** `email.json`'s `local` is a
drifted copy of `username.json`, and no shipped file yet uses a held path, an drifted copy of `username.json`, and no shipped file yet uses a held path, an
operand or a reference. Fixed in the data fill before the first tag, when the operand or a reference. Fixed in the data fill before the first tag, when the
+36 -9
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@@ -41,7 +41,7 @@ brace, a bracket or a quote, so the two cannot collide (see
| `-s`, `--seed N` | reproducible output | | `-s`, `--seed N` | reproducible output |
| `-n`, `--repeat N` | render the value N times (up to 1048576), each an independent draw, streamed | | `-n`, `--repeat N` | render the value N times (up to 1048576), each an independent draw, streamed |
| `--separator S` | between repeated values (default a newline) | | `--separator S` | between repeated values (default a newline) |
| `--format F` | `text` (default), `json`, `csv` or `sql` — a record's columns, one per line | | `--format F` | `text` (default), `json`, `csv` or `sql` — a record's columns, one record per row |
| `--table T` | the INSERT target for `--format sql` (default: the path's last segment, or `records` for an inline template) | | `--table T` | the INSERT target for `--format sql` (default: the path's last segment, or `records` for an inline template) |
| `--list` | print every path, then exit | | `--list` | print every path, then exit |
| `--version`, `-h`, `--help` | print, then exit | | `--version`, `-h`, `--help` | print, then exit |
@@ -81,7 +81,7 @@ For structured output a record writes the row for you.
### Records ### Records
A record is a template seen as columns: its fields are the columns, its `format` A record is a template seen as columns: its fields are the columns, its `format`
the whole. `--format json|csv|sql` streams a record per line; the library's the whole. `--format json|csv|sql` streams one record per row; the library's
`Record` (below) hands back the columns. Every column is a string — this is the `Record` (below) hands back the columns. Every column is a string — this is the
out-of-scope of typed scalars, see [Decisions](#decisions). Save out-of-scope of typed scalars, see [Decisions](#decisions). Save
`mydata/users.json`: `mydata/users.json`:
@@ -103,11 +103,22 @@ fejkdata --seed 1 --data-path ./mydata --format sql --table people users # INSER
``` ```
`--repeat` streams that many records — newline-delimited JSON (one object per `--repeat` streams that many records — newline-delimited JSON (one object per
line, NDJSON), a CSV row per line after a header, or an INSERT per line in SQL. line, NDJSON), a CSV row after a header, or an INSERT in SQL. To fold NDJSON into
To fold NDJSON into a single array, `fejkdata … --format json | jq -s .`. Only a a single array, `fejkdata … --format json | jq -s .`. Only a category-level
category-level template is a record; a field, choice or folder errors. Column template is a record; a field, choice or folder errors, and so does a `repeat` on
identifiers are double-quoted in SQL, so a hyphenated field like `postal-code` the template itself, which composes the format into one string rather than
stays valid. projecting columns — ask for more records with `--repeat`. A `repeat` on a column
is fine.
A column carrying a newline keeps it inside the quoted CSV field or the SQL string
literal, so a row can span physical lines: read the stream with a CSV or SQL
parser rather than splitting it on newlines.
The SQL is ANSI — identifiers in double quotes, a literal quote doubled (`''`),
backslashes passed through — so a hyphenated field like `postal-code` stays a
valid identifier. PostgreSQL and SQLite take it as written; MySQL and MariaDB need
`ANSI_QUOTES` and `NO_BACKSLASH_ESCAPES` set first, or they read `"users"` as a
string and a backslash as an escape.
A record written only to emit columns still needs a `format` — the grammar's one A record written only to emit columns still needs a `format` — the grammar's one
required key — so `"format": ""` carries the fields with an inert format: it required key — so `"format": ""` carries the fields with an inert format: it
@@ -146,7 +157,7 @@ r, err = f.FakeRecord(`{"format":"{x}","x":["a","b"]}`) // compile + render inli
| `WithDataFS(fsys)` | layer an `fs.FS`, such as your own `embed.FS` | | `WithDataFS(fsys)` | layer an `fs.FS`, such as your own `embed.FS` |
| `WithoutShippedData()` | load only what you give | | `WithoutShippedData()` | load only what you give |
A `*Record` carries its columns via `Fields()`, and serializes them with `JSON()` A `*Record` carries its columns via `Columns()`, and serializes them with `JSON()`
(one object), `CSVHeader()`/`CSVLine()`, or `SQLInsert(table)` — the same three (one object), `CSVHeader()`/`CSVLine()`, or `SQLInsert(table)` — the same three
shapes the CLI's `--format` streams. `Record` and `FakeRecord` take a record; a shapes the CLI's `--format` streams. `Record` and `FakeRecord` take a record; a
path or template that is not one — a bare string, a choice, or a folder — errors. path or template that is not one — a bare string, a choice, or a folder — errors.
@@ -529,7 +540,23 @@ tokens add cost in proportion to the output.
time, the rule a format string already follows. Only references share: a sibling time, the rule a format string already follows. Only references share: a sibling
field is local to its own column, so a `first` column does not silently bind to field is local to its own column, so a `first` column does not silently bind to
a `first` in the column next to it. a `first` in the column next to it.
- **Filling a Go struct is out of scope.** `Record.Fields()` returns the columns a
The string view of that same template does not share. `Fake` renders each
sibling field as its own expansion, so a `{/currency.code}` field beside a
`{/currency.symbol}` field is two draws and may render `EUR $`; writing both
references in one `format` holds them together, as
[One draw, one spelling](#one-draw-one-spelling) says. The scope is what makes a
row coherent when the columns *are* the output, and there the caller cannot fall
back on one format string. Widening it to every render would change what `Fake`
has emitted since the start, for a correlation a single format already reaches.
- **A record's column set is fixed before the first draw.** Only a category-level
template is a record: a path descending into a field, or naming a folder or a
choice, errors. A tail may pass through a choice whose variants carry different
fields, so the columns — and with them the CSV header written once ahead of every
row — would vary per draw. A fixed column set is what the CSV and `INSERT`
contracts rest on, so the restriction holds even where a particular choice would
happen to agree.
- **Filling a Go struct is out of scope.** `Record.Columns()` returns the columns a
caller maps onto a struct themselves, casting each string to the field's type. caller maps onto a struct themselves, casting each string to the field's type.
gofakeit's `fake:"{firstname}"` tags reflect over an arbitrary struct type and gofakeit's `fake:"{firstname}"` tags reflect over an arbitrary struct type and
cast into its fields — a different concern from "data lives in JSON", and one cast into its fields — a different concern from "data lives in JSON", and one