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SchemaCrawler

Free database schema discovery and comprehension tool

Extensions with Catalog Attributes

SchemaCrawler can read and incorporate user-provided metadata in the form of table and column remarks, and weak association definitions, and alternate key specifications from a YAML file. Examples of attributes file are shown below. Then you can run SchemaCrawler with a --attributes-file <path> command-line option.

SchemaCrawler needs Jackson jars on the classpath to read the YAML file, and these provided with the SchemaCrawler download.

Adding Table and Column Remarks

You can read and incorporate table and column remarks into the SchemaCrawler schema by creating a file like the one below. These remarks will be show in SchemaCrawler output. SchemaCrawler does not allow you to provide remarks for external tables or columns.

name: catalog
tables:
- catalog: PUBLIC
  schema: BOOKS
  name: AUTHORS
  remarks:
  - Overwritten remarks line 1
  columns:
  - name: FIRSTNAME
    remarks:
    - Overwritten remarks line 1
    - Overwritten remarks line 2
    attributes:
      tag1: tagvalue1
  - name: LASTNAME
    remarks:
    - Overwritten remarks line 1

Creating Weak Associations

You can create weak associations between columns of two tables (or even the same table) by creating a file like the one below. These weak associations will be shown in SchemaCrawler output and diagrams.

Weak associations can be between columns of tables of the SchemaCrawler schema and columns in external schemas. This is useful for tracking data lineage or other types of associations. You can provide remarks for weak associations which will also be shown in SchemaCrawler output. SchemaCrawler does not allow you to provide column references between two external tables.

Also see more information on how SchemaCrawler can infer weak associations.

name: catalog
weak-associations:
- name: multi_line_remarks
  referenced-table:
    catalog: PUBLIC
    schema: BOOKS
    name: AUTHORS
  referencing-table:
    catalog: PUBLIC
    schema: BOOKS
    name: BOOKS
  column-references:
    ID: ID
  remarks:
  - "Some remarks line 1"
  - "Some remarks line 2"
- name: multi_remarks_reference
  referenced-table:
    catalog: PUBLIC
    schema: PUBLISHER SALES
    name: SALES
  referencing-table:
    catalog: PRIVATE
    schema: ALLSALES
    name: REGIONS
  column-references:
    POSTALCODE: POSTALCODE
    COUNTRY: COUNTRY
  remarks:
  - "Other remarks line 1"
  - "Other remarks line 2"

Specifying Alternate Keys

You can specify alternate keys in tables by creating a file like the one below. These alternate keys will be shown in SchemaCrawler output and diagrams.

SchemaCrawler does not allow you to provide alternate keys in an external tables, or a column that is not in the database schema metadata.

name: catalog
alternate-keys:
- name: 1_alternate_key
  catalog: PUBLIC
  schema: BOOKS
  table: BOOKAUTHORS
  columns:
    - BOOKID
    - AUTHORID
  remarks:
  - "Indicate that this key is being used as a primary key"