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1Clear out junk files and repair common Windows errors2Fix the driver behind crashes, sound loss and screen glitches3Repair Windows errors before they cause bigger problemsFor an existing PostgreSQL database, start with a live diagram in a database client if you want to explore tables and declared foreign-key relationships. Choose generated documentation when the goal is a browsable reference, or a curated diagram when readers need a clear view of one subsystem rather than every object. The right choice depends on scope, relationship fidelity, and how you plan to share the result.
An entity-relationship diagram (ERD) maps tables and their declared relationships. If a relationship is not represented by a database constraint, a generated ERD may not show it; column names alone do not establish that two fields are related.
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How the five approaches differ
| Approach | Best fit | Scope and input | Documented output or interaction |
|---|---|---|---|
| pgAdmin ERD tool | Quickly inspect an existing database from pgAdmin | Generate from a database, schema, or table. Database scope includes tables across schemas; schema scope is limited. | Save diagrams, download an image, add notes, auto-align tables, and generate SQL from a design. pgAdmin documentation |
| DBeaver diagrams | Explore broad schemas or assemble a smaller view of selected tables | Existing tables and schemas, or a custom diagram combining chosen tables | Rearrange entities, adjust displayed details, search, generate SQL, and export or print. Diagrams are read-only by default; Edit mode stages changes as SQL. DBeaver diagram documentation and diagram guide |
| DataGrip diagrams | Visualize a database while working in DataGrip | Data source, schema, or table | Show or hide non-key columns and save as UML or PNG. DataGrip database diagrams |
| SchemaSpy | Generate browsable database documentation | Standalone application configured to connect to PostgreSQL | Generates browsable output in a directory; setup and output depend on configuration. SchemaSpy project README |
| Curated or diagram-as-code approach | Explain a subsystem, workflow, or selected relationships | Maintain or import a schema representation; scope is chosen by the author | Can produce a focused diagram and keep its source alongside documentation. Confirm the chosen tool’s import support and fidelity; no specific PostgreSQL import workflow is established here. |
Choose by the question you need the diagram to answer
For a fast overview in pgAdmin
pgAdmin’s ERD tool can generate a diagram from a database, schema, or table. The database-level option fetches tables from all schemas and plots foreign-key links. The schema-level option narrows the view to one schema and removes links to tables in other schemas. That distinction matters when relationships cross schema boundaries: a schema-only view is not a complete database-wide ERD. See the pgAdmin ERD documentation for its scope and controls.
Beyond generating a view, pgAdmin documents saving diagrams, downloading an image, adding notes, auto-aligning tables, and generating SQL from a design. It is a natural first option if you already administer the database in pgAdmin and need a diagram or static image rather than a separate documentation site.
#1 Best Overall
For broad exploration plus a hand-picked view in DBeaver
DBeaver documents diagrams for existing tables and schemas, as well as custom diagrams that combine selected tables. That makes it useful when you want both a larger schema view and a smaller diagram for one area. The editor can rearrange entities, change displayed details, search, generate SQL, and export or print; see the diagram documentation and user guide.
Diagrams are read-only by default. In Edit mode, actions such as adding tables, columns, or foreign keys produce SQL for review and execution. Treat that as a route to proposed database changes, not as an automatic edit: inspect the generated SQL before running it. Export options can depend on the DBeaver edition, so check the documentation for the edition you use rather than assuming every format is available to all users.
Rank #2
For diagrams inside DataGrip
DataGrip supports diagrams at data-source, schema, and table scope. You can hide or show non-key columns and save a diagram as UML or PNG, according to the DataGrip documentation. It suits a workflow where database browsing and visual inspection happen in the same environment. The cited documentation is labeled DataGrip 2026.2; pricing and licensing are not established here.
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SchemaSpy is a standalone application rather than a desktop database GUI. Its project README describes connecting to PostgreSQL and generating browsable output in a directory. Consider it when the deliverable is documentation people can browse, rather than a canvas for live exploration. Connection setup and generated output depend on configuration; the README description does not establish every output format or current release status.
For a focused diagram you maintain
A curated diagram can omit unrelated tables to explain one subsystem, business workflow, or set of important relationships. A diagram-as-code process may keep a source representation with other documentation, but the specific tool and PostgreSQL DDL support need to be checked for your use case. Do not assume an importer recognizes every constraint or object type: validate the result against the database, especially where relationship accuracy matters.
Check scope and relationship fidelity before sharing
- Confirm what was included. A diagram may represent one table, one schema, selected tables, or a whole database. Record the scope so readers do not mistake a focused view for a complete map.
- Check cross-schema links. In pgAdmin, a schema-level ERD removes links to tables outside that schema; use database scope when those relationships matter.
- Distinguish constraints from inferred meaning. A foreign-key link is a declared database relationship. Similar column names or application conventions may imply a business relationship, but a diagram generator should not be assumed to infer it.
- Refresh after schema changes. Live database tools inspect the database, while maintained or imported representations can become stale. Verify that the diagram reflects the current schema before relying on it.
- Keep large views readable. If an all-database diagram is crowded, use a table-centered or custom selection, or create a curated view. State what the smaller diagram leaves out.
- Match the output to the audience. An editable client view suits exploration; a saved image is easy to circulate but static; generated browsable documentation suits reference use; a curated diagram favors clarity over completeness.
A practical selection path
- Decide the scope. Choose a table or subsystem for focused explanation, one schema for a bounded view, or the database when cross-schema relationships must remain visible.
- Choose the workflow. Use pgAdmin, DBeaver, or DataGrip for client-based inspection; consider SchemaSpy when you want browsable generated documentation; use a curated diagram when a complete map would obscure the point.
- Verify relationships. Check that important links correspond to declared constraints, and annotate meaningful relationships that are not encoded as foreign keys.
- Check freshness and output. Refresh a live view after database changes, or update a maintained representation. Export or save in the form the intended readers can use, and check edition-specific availability where relevant.
- Review before acting on generated SQL. If a diagram editor can create SQL, inspect the proposed statements before executing them against a database.
PostgreSQL terms that matter when reading a diagram
A PostgreSQL database can contain schemas, which organize objects such as tables. The official PostgreSQL 18 documentation on schemas explains that structure. When interpreting an ERD, keep the database, schema, table, and declared-constraint levels distinct: a view limited to one schema may not show connections to tables elsewhere in the database.
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