SQLite can be described as efficient self-contained SQL relational database engine. This DBMS is centered on economy, efficiency, independence and simple design which makes it ideal choice as local data storage for individual applications and devices. However, compared with other advanced database management systems, SQLite doesn’t support client/server model. Consequently it can’t be employed to execute a shared repository of enterprise data.
In light of this fact it’s not thrilled that lots of companies give consideration to migrating their databases to more effective and robust DBMS. To eliminate the restrictions mentioned above, an individual may give consideration to migration from SQLite to PostgreSQL having in mind essential benefits of PostgreSQL:
- Sophisticated object-relational DBMS having virtually all possible database features like sub-selects, transactions, user-defined types and much more
- PostgreSQL is probably the most scalable and reliable database systems
- Just like SQLite, PostgreSQL is a freeware and perhaps better it is open-source
- The same implementation of logic type: unlike other popular DBMS, both SQLite and PostgreSQL store true values as ‘t’ and false as ‘f’
Migrating from SQLite to PostgreSQL involves moving data and schema structures from one database system to another. While both SQLite and PostgreSQL are relational database management systems (RDBMS), they have differences in terms of features, scalability, and performance. Here are some key points to consider when migrating from SQLite to PostgreSQL:
- Data Types. SQLite and PostgreSQL support similar data types, but they may have different names and behaviors. It’s important to review and map the corresponding data types during the migration process to ensure compatibility and data integrity.
- SQL Compatibility. SQLite and PostgreSQL use similar SQL syntax, but there are differences in certain functions, syntax, and query optimization strategies. It’s crucial to review and modify any queries, stored procedures, or triggers that may not be compatible with PostgreSQL.
- Schema and Tables. PostgreSQL supports more advanced schema management features compared to SQLite. During migration, you need to recreate tables, indexes, constraints, and other schema objects in PostgreSQL based on the existing SQLite schema. You may need to adjust data types, primary keys, and foreign key constraints accordingly.
- Data Migration. Moving data from SQLite to PostgreSQL typically involves exporting data from SQLite and importing it into PostgreSQL. You can use various methods such as CSV exports/imports, SQL dump files, or specialized migration tools to facilitate the data transfer. Be mindful of potential differences in data formatting, date and time representations, and encoding when performing the migration.
- Application Code Changes. If your application directly interacts with the database through SQL queries, you might need to update the code to use PostgreSQL-specific syntax or APIs. Additionally, review any SQLite-specific functions or features used in the application and find the corresponding equivalents in PostgreSQL.
- Testing and Validation. After completing the migration process, thoroughly test the application to ensure that it functions correctly with the PostgreSQL database. Validate the data consistency, application behavior, and performance to identify any issues that may have arisen during the migration.
- Performance Considerations. PostgreSQL offers advanced performance optimization features, such as query optimization, indexing options, and advanced caching mechanisms. Take advantage of these capabilities to tune your application for better performance and scalability.
Below this whitepaper explores available solutions that can partially or fully automate database migration from SQLite to PostgreSQL.
Migrating SQLite to PostgreSQL through CSV format
Probably the simplest technique of doing SQLite to PostgreSQL migration would be to export the source database into intermediate Comma Separate Values format after which import it to PostgreSQL. SQLite databases could be exported into CSV format below:
sqlite> .headers on
sqlite> .mode csv
sqlite> .output data.csv
sqlite> SELECT * FROM customers;
sqlite> .quit
After running these statements specified columns of table ‘customers’ will be exported into ‘data.csv’ file.
The next aspect of the migration process can be carried out via free pgloader tool offered at http://pgloader.io. To load CSV data into PostgreSQL database with pgloader you need to define some details about the operation. Below is a good example:
LOAD CSV
FROM ‘path/to/file.csv’ (x, y, a, b, c, d)
INTO postgresql:///pgloader?csv (a, b, d, c)
WITH truncate,
skip header = 1,
fields optionally enclosed by ‘”‘,
fields escaped by double-quote,
fields terminated by ‘,’
SET client_encoding to ‘latin1′,
work_mem to ’12MB’,
standard_conforming_strings to ‘on’
BEFORE LOAD DO
$$ drop table if exists csv; $$,
$$ create table csv (
a bigint,
b bigint,
c char(2),
d text
);
$$;
If the source SQLite data includes national non-ANSI symbols and isn’t saved in Unicode code page, some extra processing may be required. When this happens the database migration specialist need to do the required conversion of charset applying special script or program.
Commercial Software
You will find commercial software solutions that can perform complete migration from SQLite to PostgreSQL with a bit of clicks of mouse button. One of those is SQLite to PostgreSQL converter by Intelligent Converters. This product offers all required functionality for efficient conversion:
- All versions of PostgreSQL are supported including Azure
- Option to modify resulting table structure
- Convert indexes and relationships between tables
- Stores conversion settings into profile
- Option to merge or synchronize existing PostgreSQL database with SQLite data
- Option to export SQLite database into PostgreSQL dump file containing SQL statement to create objects and to load the data
- Command line support
