Versatile tool for managing database models, converting them to formats like PostgreSQL, kddl, and PlantUML. Offers reverse engineering, supports various identifiers, and handles schemas and tables.
Kddl is a Swiss army knife for database models. Define your schema once, generate everything else (documentation, SQL scripts, code).
Kddl can be used as a CLI tool, a library, a Gradle plugin, or a Maven plugin. It is multiplatform (jvm, js, linux, macos, windows).
┌─────────────┐
┌──>│ PostgreSQL │
│ └─────────────┘
│ ┌─────────────┐
┌─────────────┐ ├──>│ HyperSQL │
│ .kddl file │───┐ │ └─────────────┘
└─────────────┘ │ ┌──────┐ │ ┌─────────────┐
├──>│ kddl │─┼──>│ PlantUML │
┌─────────────┐ │ └──────┘ │ └─────────────┘
│ JDBC source │───┘ │ ┌─────────────┐
└─────────────┘ ├──>│ KDDL │
(jvm only) │ └─────────────┘
│ ┌─────────────┐
└──>│ Kotlin │ (with skorm plugin)
└─────────────┘
This tool is fully functional but still maturing. If you try it, be sure to give some feedback!
kddl [OPTIONS] > [output_file]
Options:
-i, --input -> mandatory; input file or JDBC URL (with credentials)
-f, --format -> mandatory; output format (value should be one of [kddl, plantuml, postgresql])
-d, --driver -> jdbc driver, needed when input is a JDBC URL (classname, must be present in the classpath)
-q, --quoted -> quoted identifiers
-u, --uppercase -> uppercase identifiers
-n, --no-idempotent -> disable IF NOT EXISTS clauses in SQL output
-h, --help -> Usage info
Here's the example.kddl file, which should be enough to understand the syntax by example.
To generate the plantuml graph definition script for this model, do:
kddl -i example.kddl -f plantuml > example.pu
plantuml -Tpng example.pu
And here's the result:
You may need to install plantuml, with something like sudo apt install plantuml on linux platforms.
To generate the PostgreSQL creation script for this model, do:
kddl -i example.kddl -f postgresql > example.sql
To do the reverse, aka generate the kddl model file from a running JDBC database, you can do:
kddl -i jdbc://...<jdbc URL with credentials> -f kddl > output.kddl
plugins {
id("com.republicate.kddl") version "0.18"
}
kddl {
model.set(file("src/main/kddl/schema.kddl"))
sql.set(file("$buildDir/generated-resources/main/init.sql"))
}
Then run:
./gradlew generateSQL
Available formats: POSTGRESQL, HYPERSQL, PLANTUML, KDDL
Options:
model (required) — source .kddl filesql — output file (default: )You'll need to have gradle installed.
Clone and build:
git clone https://github.com/arkanovicz/kddl.git
cd kddl
./install.sh
To install the kddl command everywhere, assuming that ~/bin is in your path:
ln -s ~/<path_to_kddl_repository>/kddl.sh ~/bin/kddl
Please adapt the installation and run scripts.
./gradlew build
feature/parse-ddl branch)enum(...) types are named after the field; two inline enums with the same field name across different tables will clash. Use a named enum (enum X(...) then field X) to share a type explicitly.// Include other KDDL files (paths relative to current file)
// include 'shared/types.kddl'
// include 'common.kddl'
// Definition for database geo
// Supported data types:
// boolean, integer, bigint, serial, long, float, double, numeric(n,p), money,
// time, timetz, date, timestamp, timestamptz, interval, char, char(n), varchar(n), text,
// enum(value1, value2, ...) or enum('value1', 'value2', ...), uuid, json, blob, clob, varbit
// a database contains options and schemas
database geo {
// a schema contains tables and links
schema infra {
// standalone enum declaration (values can be quoted or unquoted)
enum zone_type(urban, rural, industrial)
// a table contains fields, either given a type or a destination table
table zone {
type zone_type // reference to declared enum
*code varchar(10) // '*' stands for 'part of pk', otherwise pk is generated as needed
!name varchar(50) // '!' stands for unique
description text? // '?' stands for nullable field
active boolean = false // default value
}
table department : zone // inherit a table from another (for engines which support table inheritance like PostgresQL)
table city : zone { hasTrain boolean? } // declarations can be inlined
table link {
distance integer
src_id --> zone // mandatory foreign key field
dst_id --> zone
hub_id --> zone? (down) // nullable foreign key field
}
city *--> department (up) // plantuml arrow direction can be specified
// UML one-liner chains: declares multiple relations in one statement
// company --* department --* team --* employee
// equivalent to: company --* department ; department --* team ; team --* employee
}
schema client {
table contact {
// no primary key definition; see below
// gender, lastname, firstname // field types are optional for plantuml (use a coma to disambiguate)
gender char? // field types are mandatory for postgresql
firstname varchar(200)
+lastname varchar(200) // field is indexed
!(firstname, lastname) // composite unique constraint; '+(a, b)' declares a composite index
// constraint groups accept a partial-index condition (PostgreSQL only):
// !(a, b) where c is null — also 'where c is not null', 'where flag', 'where not flag'
}
table location {
name varchar(50) = 'untitled' // string literals use single quotes
nature enum('depart', 'arrival') as LocationNature // enum with custom type name
address text?
}
location *--> contact // will generate the implicit "contact_id serial" primary key in contact
location *--> infra.zone // foreign key referencing a table in another schema
// Chain syntax with nullable markers:
// category? *--* product? --* review
// The '?' after a table makes FKs involving that table nullable
// For finer control, use separate declarations:
// category *--* product?
// product --* review
}
}
<plugin>
<groupId>com.republicate.kddl</groupId>
<artifactId>kddl-maven-plugin</artifactId>
<version>0.18</version>
<executions>
<execution>
<goals>
<goal>generate-sql</goal>
</goals>
<configuration>
<model>${project.basedir}/src/main/kddl/schema.kddl</model>
<sql>${project.build.directory}/generated-resources/kddl/init.sql</sql>
<format>POSTGRESQL</format>
</configuration>
</execution>
</executions>
</plugin>
target/generated-resources/kddl/init.sqlformat — output format (default: POSTGRESQL)quoted — use quoted identifiers (default: false)uppercase — use uppercase identifiers (default: false)Surfaced from shared tags and platforms — no rankings paid for.