# Data schema descriptor ## Schema description The schema must be expressed as an XML file. This file should be located at a core addon module and be named plugin-ddl.xml. This DDL file can contain descriptions for tables, indexes and foreign keys. ## Tables A table is composed of a <table> entity containing one or more <column> entities:

Attributes for <table> entity
name	Table name

Attributes for <column> entity
name	Column name
type	It can have one of the following values, as stated at java.sql.Types class: INTEGER LONG BOOLEAN / BIT FLOAT DOUBLE VARCHAR CHAR DATE CLOB BLOB
length	Optional column size.
notNull	true if it cannot contain null values
primaryKey	true if it's part of the primary key. The primary key will be composed of all attributes marked as primary key. The order of them will be the same as their appear order at XML fi

## Foreign keys A foreign key is declared using the <foreignKey> entity. It will contain one or more <column> entities. Each columns identifies a member of the foreign key. It will also contain one or more <foreignColumn> entities. Each foreignColumn entity specifies the name of the corresponding column at the foreign table.

Attributes for entity <foreignKey>
name	Foreign key name
tableName	Table name
foreignTableName	Name of master table

Attributes for <column> entity
name	Column containing the foreign key

Attributes for <foreignColumn> entity
name	Column containing the foreign key

## Indexes An index is declared using the <index> entity. It will contain one or more <column> entities. Each column identifies a member of the index.

Attributes for <index> entity
name	Index name
tableName	Table name
unique	true if no duplicated keys will be allowed

Attributes for entity <column>
name	Column to be indexed

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## Sample plugin-ddl.xml ```XML

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