Database Comparison

DbClone includes a standalone comparison feature that lets you diff two databases without copying anything.

Opening the Comparison

1. Select source and destination connections on the main screen
2. Switch the toolbar to Compare mode
3. Click the run button (▶) — or press Ctrl+Shift+C

What Gets Compared

The comparison checks multiple object types with varying levels of detail:

Table selection scopes the comparison

If a table selection is active on the source panel, only the selected tables are compared — target tables outside the selection are ignored and not reported as differences. Non-table objects are compared in full.

Tables (structural DDL diff)

Beyond presence and row counts, DbClone performs a detailed structural comparison of each table:

• Columns — name, data type, nullability, default values, identity/generated columns
• Primary keys — column list comparison
• Foreign keys — name, columns, referenced schema/table/columns, update/delete rules
• Check constraints — expression comparison with normalization (handles PostgreSQL decompiler variance across versions, including partition-inherited constraints)
• Unique constraints — name and column list

Other Object Types

• Indexes — presence and definition (columns, uniqueness, filter)
• Views — presence and query definition
• Materialized Views — presence and query definition
• Functions / Procedures — presence and body definition
• Sequences — presence and configuration (data type, increment, bounds, cycling); identity backing sequences are excluded (non-deterministic names across databases)
• Triggers — presence and definition (timing, events, function, level)
• Enums — presence and label list
• Domains — presence and definition (base type, constraints)
• Composite Types — presence and attribute definitions

Result Statuses

Each compared object gets a status:

Status	Icon	Meaning
Identical	🟢	Same object, same definition/row count
Notice	🟡	Object matches structurally but carries a non-structural note (e.g. schema owner differs, partition CHECK normalization artifact). Does not count as a real difference
Different	🟠	Object exists on both but definition or row counts differ
Missing Source	🔴	Object exists on destination but not source
Missing Dest	🔵	Object exists on source but not destination
Skipped	⚪	Object exists in both but could not be compared (e.g. insufficient permissions)
Error	⚠️	Couldn't compare (permission issue, timeout)

Notice vs Different

The Notice status is one level below Different. It indicates a cosmetic or environmental difference that does not represent a real structural divergence between the databases. Examples:

• A CHECK constraint expression that PostgreSQL decompiles differently across versions (normalized automatically)
• A CHECK constraint difference on a partition child (inherited from parent — the parent is the source of truth)
• Schema owner differences

Notices are shown in the results but do not count toward the "differences" total.

Comparison Modes

Same as validation modes:

• Row Count — fast, compares only COUNT(*)
• Checksum — compares MD5 of content
• Full — count + checksum

Export Report

After comparison, click Report in the toolbar to open the comparison report window. From its toolbar you can export results as:

• HTML — formatted report for sharing
• Markdown — for documentation or version control
• JSON — machine-readable format
• Copy to Clipboard — plain text summary

Use Cases

• Pre-copy check — see what's different before running a copy
• Post-copy verification — confirm the copy was successful
• Drift detection — check if staging has drifted from production
• Audit — document database state at a point in time