SQLite to SQL Server Migration: A Complete Guide

By Bill Crawford  ·  February 2026  ·  10 min read  ·  Last updated February 26, 2026

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SQLite is the most deployed database engine in the world — it runs inside phones, embedded systems, desktop apps, and prototype services. But when an application outgrows single-file storage and needs concurrent access, network clients, or enterprise features like row-level security and full-text indexing, SQL Server is a natural destination. This guide covers the practical steps and decisions involved in moving a SQLite database to SQL Server.

Why Migrate from SQLite to SQL Server?

SQLite is file-based and single-writer. It is excellent for local storage but does not support concurrent writes from multiple connections, role-based security, stored procedures, or replication. SQL Server provides all of these plus advanced indexing, partitioning, Always On availability groups, and integration with enterprise tooling.

Common migration triggers include moving from a prototype to production, scaling a desktop application to a client-server architecture, compliance requirements that mandate audit logging and access control, or consolidating data from multiple SQLite files into a central data warehouse.

Key Challenges

SQLite and SQL Server differ in several fundamental ways that a migration must address:

• Dynamic typing vs strict typing. SQLite allows any value in any column regardless of declared type. SQL Server enforces column types strictly. You must choose correct target types for every column.
• Auto-increment behavior. SQLite's AUTOINCREMENT and INTEGER PRIMARY KEY differ from SQL Server's IDENTITY property. Migrating existing values requires SET IDENTITY_INSERT ON.
• Foreign key enforcement. SQLite has foreign key support but it is off by default (PRAGMA foreign_keys = ON). SQL Server enforces foreign keys by default — tables must be created and populated in dependency order.
• String handling. SQLite stores text as UTF-8. SQL Server uses NVARCHAR (UTF-16) for Unicode. Mapping TEXT to NVARCHAR is the safe default.
• Index key size limits. SQL Server limits index keys to 900 bytes (1700 for nonclustered). SQLite has no such limit. String columns used in indexes or foreign keys may need length constraints.

Type Mapping: SQLite → T-SQL

SQLite has five storage classes: NULL, INTEGER, REAL, TEXT, and BLOB. Column type declarations in SQLite are advisory — they influence type affinity but do not enforce types. SQL Server has dozens of specific types. The table below shows recommended default mappings:

Schema Translation

Each SQLite CREATE TABLE needs to be translated into T-SQL syntax. Key differences include:

• Identifiers. SQL Server uses square brackets ([TableName]) rather than double quotes.
• Default values. SQLite's CURRENT_TIMESTAMP becomes GETDATE() in T-SQL. datetime('now') also maps to GETDATE().
• Schema prefix. SQL Server tables live in a schema, typically dbo. Every table reference should include the schema: [dbo].[TableName].
• Index creation. SQLite CREATE INDEX statements translate directly, but column types in the index must respect the 900-byte key limit.

-- SQLite
CREATE TABLE users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    name TEXT NOT NULL,
    email TEXT UNIQUE,
    created_at DATETIME DEFAULT CURRENT_TIMESTAMP
);

-- SQL Server (T-SQL)
CREATE TABLE [dbo].[users] (
    [id] BIGINT IDENTITY(1,1) NOT NULL,
    [name] NVARCHAR(MAX) NOT NULL,
    [email] NVARCHAR(450) NULL,
    [created_at] DATETIME2 DEFAULT GETDATE(),
    CONSTRAINT [PK_users] PRIMARY KEY CLUSTERED ([id])
);
CREATE UNIQUE NONCLUSTERED INDEX [IX_users_email] ON [dbo].[users] ([email]);

Note how email gets NVARCHAR(450) rather than NVARCHAR(MAX) — it is part of a unique index and must fit within the 900-byte key limit (450 × 2 bytes per Unicode character = 900 bytes).

Data Migration Strategy

For small tables, a single INSERT INTO ... VALUES statement works. For tables with thousands or millions of rows, batch inserts are essential to avoid transaction log bloat and timeout issues.

A practical approach is to generate one INSERT statement per batch (e.g., 1,000 rows) using the multi-row VALUES syntax introduced in SQL Server 2008:

INSERT INTO [dbo].[orders] ([id], [customer_id], [total], [status])
VALUES
    (1, 42, 299.99, N'shipped'),
    (2, 17, 54.50, N'pending'),
    -- ... up to 1000 rows per batch
    (1000, 88, 120.00, N'delivered');

For tables with an IDENTITY column, wrap inserts with SET IDENTITY_INSERT [dbo].[orders] ON and OFF to preserve original ID values from the source database.

Foreign Keys and Ordering

Foreign keys must reference tables that already exist and contain the referenced rows. The safest approach is a three-phase process:

1. Create all tables without foreign key constraints, in topological order (parents first).
2. Insert all data in the same order — parent rows before child rows.
3. Add foreign key constraints with ALTER TABLE ... ADD CONSTRAINT after all data is loaded.

This avoids constraint violations during load and makes it easy to re-run data scripts without dropping constraints first.

Validation

After running all scripts, verify the migration by comparing row counts per table between the source SQLite file and the target SQL Server database. A validation script can automate this:

DECLARE @expected INT = 15420;
SELECT @actual = COUNT(*) FROM [dbo].[orders];
IF @actual = @expected
    PRINT 'PASS: orders (15420 rows)';
ELSE
    PRINT 'FAIL: orders — expected 15420, got ' + CAST(@actual AS NVARCHAR);

Beyond row counts, spot-check a sample of rows to confirm data integrity — especially columns with special characters, NULL values, or binary data.

Common Pitfalls

NVARCHAR(MAX) in Indexes

SQL Server cannot index NVARCHAR(MAX) columns. If a SQLite TEXT column is part of a primary key, unique constraint, or index, you must constrain the length. Analyze the actual maximum length of data in that column and set the type accordingly.

Boolean Columns

SQLite stores booleans as integers (0 and 1), but some applications store 'true' and 'false' as text. If your data has text booleans, add a CASE WHEN to convert them during insert.

Date Formats

SQLite stores dates as text strings (ISO 8601), real numbers (Julian day), or integers (Unix epoch). SQL Server's DATETIME2 parses ISO 8601 strings directly, but Julian day and Unix epoch values need explicit conversion.

Empty String vs NULL

SQLite distinguishes between '' (empty string) and NULL. SQL Server also distinguishes them, but some applications treat them interchangeably. Verify your application logic handles both correctly after migration.

Frequently Asked Questions

Can I migrate to Azure SQL Database instead of on-premises SQL Server?

Yes. Azure SQL Database uses the same T-SQL engine. Skip the CREATE DATABASE step (Azure manages databases at the server level) and the scripts will work as-is.

What about SQLite views and triggers?

Views and triggers use different syntax between SQLite and SQL Server. They typically need manual translation. The automated tool focuses on tables, data, indexes, and foreign keys — the bulk of the migration work.

How do I handle very large databases?

For databases over 1 GB, consider using SQL Server Integration Services (SSIS), the bcp utility, or Azure Data Factory for the data load phase. Generate the schema scripts with the browser tool, then use bulk-load tools for the data.

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