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How to Migrate from SQLite to PostgreSQL

Migrating from SQLite to PostgreSQL is typically done when an application needs to scale beyond SQLite's single-file, single-writer limitations. PostgreSQL supports concurrent writes, replication, and much larger datasets. The migration is relatively straightforward compared to other database migrations.

6

Data Type Mappings

4

Syntax Differences

4

Migration Steps

2

Free Tools

Data Type Mappings

SQLitePostgreSQLNotes
INTEGERINTEGER or BIGINTSQLite INTEGER is flexible (1-8 bytes); map to fixed PostgreSQL type
TEXTTEXT or VARCHAR(n)—
REALDOUBLE PRECISION—
BLOBBYTEA—
NUMERICNUMERIC—
INTEGER PRIMARY KEY (autoincrement)SERIAL PRIMARY KEY or GENERATED ALWAYS AS IDENTITY—

SQL Syntax Differences

Auto Increment

SQLite

INTEGER PRIMARY KEY AUTOINCREMENT

PostgreSQL

SERIAL PRIMARY KEY
Boolean

SQLite

INTEGER (0/1) for booleans

PostgreSQL

BOOLEAN

SQLite has no BOOLEAN type

Date/time functions

SQLite

datetime('now'), strftime()

PostgreSQL

NOW(), TO_CHAR()
UPSERT

SQLite

INSERT OR REPLACE / INSERT OR IGNORE

PostgreSQL

INSERT ... ON CONFLICT DO UPDATE / DO NOTHING

Step-by-Step Migration Guide

1

Export SQLite schema and data

Use SQLite's .dump command to export everything.

sqlite3 mydb.sqlite '.dump' > dump.sql
2

Convert SQL to PostgreSQL syntax

Edit the dump file: replace SQLite-specific syntax with PostgreSQL equivalents. The main changes are autoincrement, boolean handling, and some function names.

3

Load into PostgreSQL

Create the PostgreSQL database and load the converted SQL file.

createdb mydb
psql mydb < converted_dump.sql
4

Update application connection

Switch the application from SQLite driver to a PostgreSQL driver (psycopg2 for Python, pg for Node.js, etc.).

Common Issues & Solutions

SQLite's flexible typing vs PostgreSQL's strict typing

PostgreSQL enforces data types strictly. SQLite allows storing any value in any column type. Review data for type mismatches before migration.

SQLite-specific functions (datetime, strftime, etc.)

Replace SQLite date functions with PostgreSQL equivalents: datetime('now') → NOW(), strftime('%Y-%m-%d', col) → TO_CHAR(col, 'YYYY-MM-DD').

Recommended Migration Tools

pgloader

FREE

Supports SQLite → PostgreSQL migration with automatic type mapping.

sqlite3 CLI

FREE

Built-in SQLite export tool.

Frequently Asked Questions

When should you migrate from SQLite to PostgreSQL?
Consider migrating when: your application needs concurrent write access (SQLite allows only one writer at a time), database size exceeds ~1GB, you need replication or high availability, you need advanced PostgreSQL features (JSONB, full-text search, PostGIS), or you're deploying to multiple application servers that need a shared database.
Is SQLite to PostgreSQL migration easy?
Yes, it is relatively straightforward compared to other database migrations. Both databases use similar SQL syntax. The main effort is: converting the dump file syntax (autoincrement → serial, date functions), updating the application connection string, and switching the database driver library.

Ready to Migrate?

Test your PostgreSQL queries in our free SQL Playground before migrating.

Test in Playground All Migration Guides