SQL Mock Data Generator

How the SQL Mock Data Generator works

Each column row becomes a column in the table. The generator uses the same data engine as the Fake JSON Data Generator: names, companies and job titles come from built-in lists, town names are made up, emails use example.com and example.org, phone numbers use the fictional 555-01xx range and IP addresses come from the documentation ranges. Name, email and username columns in one row describe the same person.

Table and column names are always quoted for the chosen database: [brackets] for SQL Server, "double quotes" for PostgreSQL and `backticks` for MySQL. A name such as dbo.Customers is quoted part by part. Text is written as string literals with single quotes doubled, booleans become 1/0 on SQL Server and TRUE/FALSE elsewhere, and date-times are written as 'YYYY-MM-DD hh:mm:ss'. Rows are grouped into multi-row INSERT ... VALUES statements; SQL Server accepts at most 1,000 rows per statement, so that is the limit. The optional CREATE TABLE picks a column type for each field, for example UNIQUEIDENTIFIER, UUID or CHAR(36) for UUIDs, and makes the first ID column the primary key.

How to use the SQL Mock Data Generator

1. Review the example columns. Change a column name or type, select Add field for a new column, or select Remove to delete one. Use the Setting box for ranges (such as 1..100) and lists of values.
2. Enter the table name, for example customers or dbo.Customers, and choose SQL Server, PostgreSQL or MySQL.
3. Set the number of rows (1 to 1,000) and the rows per INSERT statement. Untick Include CREATE TABLE if the table already exists.
4. The SQL updates as you edit. Select Generate SQL, or press Ctrl + Enter (Cmd + Enter on a Mac), for a new set of values.
5. Copy the script or download it as a .sql file and run it against your development database.

Example

Columns id (ID), full_name (Full name), is_active (Boolean) and joined (Date and time), 3 rows, 2 rows per INSERT, SQL Server:

CREATE TABLE [customers] (
    [id] INT NOT NULL PRIMARY KEY,
    [full_name] NVARCHAR(100) NOT NULL,
    [is_active] BIT NOT NULL,
    [joined] DATETIME2(0) NOT NULL
);

INSERT INTO [customers] ([id], [full_name], [is_active], [joined]) VALUES
    (1, 'Nadia Okafor', 1, '2022-06-14 08:41:09'),
    (2, 'Hugo Varga', 0, '2024-01-30 17:05:52');

INSERT INTO [customers] ([id], [full_name], [is_active], [joined]) VALUES
    (3, 'Priya Novak', 1, '2021-11-02 12:27:44');

For PostgreSQL the same columns are created as "id" INTEGER, "full_name" VARCHAR(100), "is_active" BOOLEAN and "joined" TIMESTAMP.

Common use cases

• Seeding a local or test database with realistic customers, orders or users.
• Creating enough rows to test paging, sorting, search and reports.
• Writing repeatable demo data scripts for a new feature or a bug reproduction.
• Trying out a table design with a quick CREATE TABLE and sample rows before writing migrations.

Common errors and how to fix them

Enter a table name, or add at least one field

Both are required before any statement can be produced: the table name becomes the INSERT target, and the fields become its column list. Use the same table name as the real table you are loading.

The generated INSERT statements fail against my table

The generator does not know your real schema. Match each field's type to the column type, and make sure every NOT NULL column without a default is included.

Generated rows collide with existing primary keys

Random values can repeat keys that are already stored. Load into an empty table, or leave identity and auto-increment columns out of the insert so the database assigns them.

The data must not reach production

These are randomly generated placeholder rows. Always run generated SQL against a development or test database first, and keep a backup.

Frequently asked questions