3.1 Schema Syntax¶

qdbd reads QuickDBD's text format. It mirrors QuickDBD's own parser, so a schema that works there works here, with the same error messages.

Tables¶

# Doc comment for the table
Customer as c, cust      # aliases, comma-separated
-                        # separator: any number of dashes
CustomerId PK int
Name string

A table is a header line, a separator line of -, then column lines. A blank line ends a table; comment lines don't.
Names with spaces or dots must be quoted: "Product Catalog", "dbo.Customer".
Aliases can be used anywhere a table name is referenced.

Columns¶

name [type] [modifiers…]      # any order, case-insensitive

Token	Meaning
`int`, `varchar(200)`, `decimal(10,2)`	the type: the first word that isn't a keyword
`PK`	primary key (several `PK` columns = composite key)
`FK`	foreign key, optionally followed by a relationship: `FK >- Customer.CustomerId`
`NULL` / `NULLABLE`	nullable. Columns are NOT NULL by default
`UNIQUE`, `INDEX`	unique key, index
`IDENTITY` / `AUTOINCREMENT`	auto-generated
`default=value`, `int=27`, `string="two words"`	default value

PK can't be combined with UNIQUE or INDEX, and UNIQUE can't be combined with INDEX.

Relationships¶

Operator	Left → right
`-`	one to one
`-<`	one to many
`>-`	many to one
`>-<`	many to many
`-0`	one to zero-or-one
`0-`	zero-or-one to one
`0-0`	zero-or-one to zero-or-one
`-0<`	one to zero-or-many
`>0-`	zero-or-many to one

Inline, on the column that holds the key:

CustomerId int FK >- Customer.CustomerId

Table-level, between the header and the separator (no columns specified):

OrderLine
rel >- Product
---

Targets can be aliases; quoted names work in targets too: FK >- "dbo.Customer"."Customer Id". A relationship may be declared once (in either direction).

Comments¶

# starts a comment, except inside double quotes. Comment lines directly above a table or column, plus a comment at the end of its line, become its documentation, shown as a tooltip and in the details panel.

Settings and layout sections¶

[settings]
Zoom 100
CaseSensitive on
DefaultFieldType int

[layout]
Customer 120 80

CaseSensitive controls name lookups (off by default).
DefaultFieldType is used for columns without a type.
[layout] positions (from QuickDBD) are used for tables the layout file doesn't cover.

Where qdbd is more forgiving¶

qdbd accepts a few things QuickDBD rejects, and prints a warning for each:

tab characters
spaces inside a type: decimal(10, 2)
an explicit NOT NULL
indented table names
[layout] lines for unknown tables

qdbd check --strict turns these into errors, so a file that passes is guaranteed to paste back into QuickDBD.

One difference isn't a warning: default= values keep their case, where QuickDBD lowercases them.

Many files¶

Every file is parsed on its own; then all tables share one namespace, so foreign keys can point across files. See 3.2 Many Files, One Diagram.