Review Rules

Bytebase provides customizable SQL lint rules to check common issues in schema change process.

Different sets of rules can form different SQL Review Policies for the respective environment.

Supported rules

• Engine
  • Require InnoDB
• Naming
  • Table naming convention
  • Column naming convention
  • Auto-increment column naming convention
  • Index naming convention
  • Primary key naming convention
  • Unique key naming convention
  • Foreign key naming convention
• Statement
  • Disallow SELECT *
  • Require WHERE
  • Disallow leading % in LIKE
  • Disallow COMMIT
  • Disallow LIMIT
  • Disallow ORDER BY
  • Merge ALTER TABLE
  • INSERT statements must specify columns
  • Disallow ORDER BY RAND in INSERT statements
  • Limit the inserted rows
  • Limit affected rows
  • Dry run DML statements
  • Disallow add column with default
  • Add CHECK constraints with NOT VALID option
  • Disallow add NOT NULL constraints to an existing column
• Table
  • Require primary key
  • Disallow foreign key
  • Drop naming convention
  • Disallow partition table
  • Table comment convention
• Schema
  • Backward incompatible schema change
• Column
  • Enforce the required columns in each table
  • Column type disallow list
  • Columns no NULL value
  • Disallow changing column type
  • Set DEFAULT value for NOT NULL columns
  • Disallow ALTER TABLE CHANGE COLUMN statements
  • Disallow changing column order
  • Use integer for auto-increment columns
  • Disallow set charset for columns
  • Set unsigned attribute on auto-increment columns
  • Column comment convention
  • Maximum CHAR length
  • Auto-increment initial value
  • Limit the count of current time columns
  • Require column default value
• Index
  • Disallow duplicate column in index keys
  • Limit the count of index keys
  • Limit key type for primary keys
  • Disallow BLOB and TEXT for index keys
  • Index count limit
  • Primary key type allowlist
  • Create index concurrently
• Database
  • Drop database restriction
• System
  • Charset allow list
  • Collation allow list
  • Comment length limit

Engine

Require InnoDB

InnoDB is the default storage engine of MySQL 5.5+. It provides powerful transaction features. Normally, using InnoDB as the storage engine is the only option. Bytebase provides this rule to catch all scenarios where other engines are attempted.

How the rule works

Bytebase defaults MySQL to use InnoDB storage engine.

So if the following situation occurs, Bytebase considers this rule to be violated:

• Explicitly specify other storage engines when creating tables. e.g. CREATE TABLE t(id int) ENGINE = CSV
• Explicitly specify other storage engines when ALTER TABLE. e.g. ALTER TABLE t ENGINE = CSV
• Try to set default_storage_engine other than InnoDB. e.g. SET default_storage_engine = CSV

Support database engine

• MySQL

Naming

Table naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the table naming convention.

About convention format

Table Naming Convention uses regular expression as the format for naming pattern, and also limits the naming max length. The default maximum length is 64 characters. Length limit does not support PostgreSQL.

Some typical format

Name	Regular Expression
snake_lower_case	^[a-z]+(_[a-z]+)*$
CamelCase	^([A-Z][a-z]*)+$
lowerCamelCase	^[a-z]+([A-Z][a-z]*)*$
kebab-case	^[a-z]+(-[a-z]+)*$

How the rule works

Bytebase checks that all table names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE RENAME TO statements
• RENAME TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Column naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the column naming convention.

About convention format

Column Naming Convention uses regular expression format for naming pattern, and also limits the naming max length. The default maximum length is 64 characters. Length limit does not support PostgreSQL.

Some typical format

Name	Regular Expression
snake_lower_case	^[a-z]+(_[a-z]+)*$
CamelCase	^([A-Z][a-z]*)+$
lowerCamelCase	^[a-z]+([A-Z][a-z]*)*$
kebab-case	^[a-z]+(-[a-z]+)*$

How the rule works

Bytebase checks that all column names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE RENAME COLUMN statements
• ALTER TABLE ADD COLUMNS statements
• ALTER TABLE CHANGE COLUMN statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Auto-increment column naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the auto-increment column naming convention.

About convention format

Auto-increment Column Naming Convention uses regular expression format for naming pattern, and also limits the naming maximum length. The default maximum length is 64 characters.

Some typical format

Name	Regular Expression
id	^id$

How the rule works

Bytebase checks all auto-increment column names in DDL conforming to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Index naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the index naming convention.

About convention format

Index Naming Convention uses template format. Specifically, the template is an extended regular expression. The rest follows the regular expression rules except the part with curly braces.

For example, ^idx_{{table}}_{{column_list}}$ is a template where {{table}} is the table name and {{column_list}} is the list of the column name. So for index on user(id, name), the legal name is idx_user_id_name.

It also limits the naming max length. The default maximum length is 64 characters. Length limit does not support PostgreSQL.

How the rule works

Bytebase checks that all index names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE RENAME INDEX statements
• ALTER TABLE ADD CONSTRAINT statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Primary key naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the primary key naming convention. This rule does NOT support MySQL and TiDB. Because the name of a PRIMARY KEY is always PRIMARY in MySQL and TiDB.

About convention format

Primary Key Naming Convention uses template format. Specifically, the template is an extended regular expression. The rest follows the regular expression rules except the part with curly braces.

For example, ^pk_{{table}}_{{column_list}}$ is a template where {{table}} is the table name and {{column_list}} is the list of the column name. So for primary key on user(id, name), the legal name is pk_user_id_name.

How the rule works

Bytebase checks that all index names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER INDEX RENAME TO statements
• ALTER TABLE ADD CONSTRAINT statements

Support database engine

• PostgreSQL

Unique key naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the unique key naming convention.

About convention format

Unique Key Naming Convention uses template format. Specifically, the template is an extended regular expression. The rest follows the regular expression rules except the part with curly braces.

For example, ^uk_{{table}}_{{column_list}}$ is a template where {{table}} is the table name and {{column_list}} is the list of the column name. So for unique key on user(id, name), the legal name is uk_user_id_name.

It also limits the naming max length. The default maximum length is 64 characters. Length limit does not support PostgreSQL.

How the rule works

Bytebase checks that all unique key names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE RENAME INDEX statements
• ALTER TABLE ADD CONSTRAINT statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Foreign key naming convention

The unified naming convention is desired by developers. And the same applies to the database space. Bytebase provides this rule to unify the foreign key naming convention.

About convention format

Foreign Key Naming Convention uses template format. Specifically, the template is an extended regular expression. The rest follows the regular expression rules except the part with curly braces.

For example, ^fk_{{referencing_table}}_{{referencing_column}}_{{referenced_table}}_{{referenced_column}}$ is a template where {{referencing_table}} is the name of the referencing table, {{referencing_column}} is the list of the referencing column name, {{referenced_table}} is the name of the referenced table and {{referenced_column}} is the list of the referencing column name. So for unique key on user(id, name), the legal name is uk_user_id_name.

It also limits the naming max length. The default maximum length is 64 characters. Length limit does not support PostgreSQL.

How the rule works

Bytebase checks that all foreign key names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE ADD CONSTRAINT statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Statement

Disallow SELECT *

SELECT * introduces additional performance cost or ambiguous semantics.

For scenarios where all columns are not required, you should SELECT the columns you need to avoid getting uneeded data.

For scenarios where all columns are required, you should list all column names to avoid semantic ambiguity. Otherwise, the data consumer cannot know the column information. And SELECT * may bring additional modifications and errors when modifying the table schema.

How the rule works

Bytebase considers this rule to be violated if the SQL has SELECT *.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Require WHERE

There are countless stories about people forgetting the WHERE clause in an UPDATE or DELETE and losing data. In queries, not using WHERE can also cause performance issues.

If you are sure you need to act on all data, use WHERE 1=1 to remind yourself of the consequences of that action.

How the rule works

Bytebase considers this rule to be violated if the SQL has no WHERE clause.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow leading % in LIKE

Database cannot use an index to match entries when there is a leading wildcard. It can cause serious performance problems because it may scan the entire table.

How the rule works

Bytebase considers this rule to be violated if the SQL has leading wildcard LIKE.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow COMMIT

Disallow using COMMIT statement.

How the rule works

Bytebase alerts users if there exists COMMIT statement.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow LIMIT

Disallow LIMIT clause for INSERT, UPDATE and DELETE statements.

How the rule works

Specifically, Bytebase checks:

• INSERT statements
• UPDATE statements
• DELETE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Disallow ORDER BY

Disallow ORDER BY clause for UPDATE and DELETE statements.

How the rule works

Specifically, Bytebase checks:

• UPDATE statements
• DELETE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Merge ALTER TABLE

For readability, it's better not to use multiple ALTER TABLE statements for the same table.

How the rule works

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

INSERT statements must specify columns

For readability, it's better to explicitly specify columns for INSERT statements, such as INSERT INTO table_t(id, name) VALUES(...).

How the rule works

Specifically, Bytebase checks:

• INSERT statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow ORDER BY RAND in INSERT statements

The ORDER BY RAND() clause is not necessary for INSERT statements.

How the rule works

Specifically, Bytebase checks:

• INSERT statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Limit the inserted rows

Alert users if the inserted rows exceed the limit.

How the rule works

• For INSERT INTO ... VALUES(...) statements, Bytebase checks the count of value list.
• For INSERT INTO ... SELECT ... statements, Bytebase runs EXPLAIN statements for them and check the rows in EXPLAIN statement results.

Support database engine

• MySQL
• PostgreSQL

Limit affected row limit

Alert users if the affected rows in UPDATE or DELETE exceed the limit.

How the rule works

For UPDATE and DELETE statements, Bytebase runs EXPLAIN statements for them and check the rows in EXPLAIN statement results.

Support database engine

• MySQL
• PostgreSQL

Dry run DML statements

Dry run DML statements for validation.

How the rule works

Dry run DML statements by EXPLAIN statements. Specifically, Bytebase checks:

• INSERT statements
• UPDATE statements
• DELETE statements

Support database engine

• MySQL
• PostgreSQL

Disallow add column with default

The PostgreSQL will lock the table and rewrite the whole table when you adding column with default value. You can separate the adding column, setting default value and backfilling all existing rows.

How the rule works

Bytebase checks all ALTER TABLE ADD COLUMN statements.

Support database engine

• PostgreSQL

Add CHECK constraints with NOT VALID option

Adding CHECK constraints without NOT VALID can cause downtime because it blocks reads and writes. You can manually verify all rows and validate the constraint after creating.

How the rule works

Bytebase checks all ALTER TABLE ADD CONSTRAINT statements.

Support database engine

• PostgreSQL

Disallow add NOT NULL constraints to an existing column

It can cause downtime because it blocks reads and writes. You can add CHECK(column IS NOT NULL) constraints with NOT VALID option to avoid this.

How the rule works

Bytebase checks all ALTER TABLE ADD CONSTRAINT statements.

Support database engine

• PostgreSQL

Table

Require primary key

In almost all cases, each table needs a primary key.

e.g. in MySQL, the InnoDB storage engine always creates a primary key if you didn't specify it explicitly or didn't create a unique key, thus making an extra column you don't have access to.

How the rule works

Bytebase considers this rule to be violated if the SQL tries to create a no primary key table or drop the primary key. If the SQL drops all columns in the primary key, Bytebase also considers that this SQL drops the primary key.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow foreign key

This rule disallows users to create foreign key in the table.

A foreign key is a logical association of rows between two tables, in a parent-child relationship. A row in a "parent" table may be referenced by one or more rows in a "child" table.

FOREIGN KEY constraints are impossible to maintain once your data grows and is split over multiple database servers. This typically happens when you introduce functional partitioning/sharding and/or horizontal sharding.

How the rule works

Bytebase considers this rule to be violated if the SQL tries to:

• CREATE TABLE statement with foreign key
• ALTER TABLE ADD CONSTRAINT FOREIGN KEY statement

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Drop naming convention

Only tables named with specific naming patterns can be deleted. This requires users to do a rename and then drop the table.

The naming convention uses regular expression format. By default the table name must have _del suffix.

How the rule works

Bytebase checks that the table names in DDL conform to the naming conventions.

Specifically, Bytebase checks:

• DROP TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow partition table

How the rule works

Bytebase checks if the SQL statement will create the partition table.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Table comment convention

Configure whether the table requires comments and the maximum comment length.

How the rule works

Bytebase checks the table comment convention.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Schema

Backward incompatible schema change

Introducing backward incompatible schema changes is one of the most common mistakes made by developers. And enforcing backward compatible schema change is the standard practice adopted by many engineering organizations. Bytebase provides the built-in backward compatible check to catch all common incompatible schema change scenarios.

How the rule works

If the following situation occurs, Bytebase considers this rule to be violated:

• Drop database
• Rename table/view
• Drop table/view
• Rename column
• Drop column
• Add primary key
• Add Unique key
• Add Foreign key
• Add check enforced
• Alter check enforced
• Modify column
• Change column

Support database engine

• MySQL
• TiDB
• PostgreSQL

Column

Enforce the required columns in each table

For most projects, you may want to enforce some columns for every table. For example, need id as identification and the primary key for each table or need created_ts and updated_ts to record creation and modification times.

You can customize which columns are required.

How the rule works

Bytebase defaults all tables to meet the requirements. If the SQL tries to define a table not having all the required columns or attempts to drop the required column, Bytebase considers this rule to be violated.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Column type disallow list

Set column type disallow list to ban column types.

How the rule works

Bytebase checks if the SQL statement creates the column type in the disallow list.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Columns no NULL value

NULL is a special value. It can cause confusion or performance issues. Bytebase provides this rule to enforce that all columns cannot have NULL value.

How the rule works

Bytebase considers this rule to be violated if the SQL defines a column allowing NULL value.

Support database engine

• MySQL
• TiDB
• PostgreSQL

Disallow changing column type

Changing column type may fail because the data cannot be converted. Bytebase provides this rule to alert you that the SQL statement would change the column type.

How the rule works

Bytebase checks if the SQL statement will change the column type.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Set DEFAULT value for NOT NULL columns

NOT NULL columns have no default value. It requires users to manually set default values for NOT NULL columns.

How the rule works

Bytebase checks if setting default values for NOT NULL columns.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Disallow ALTER TABLE CHANGE COLUMN statements

CHANGE COLUMN is a MySQL extension to standard SQL. CHANGE COLUMN can change column definition and names, or both. Most of the time, you just want to change one of two. So you need to use RENAME COLUMN and MODIFY COLUMN instead of CHANGE COLUMN to avoid unexpected modifications.

How the rule works

Bytebase checks if using ALTER TABLE CHANGE COLUMN statements.

Support database engine

• MySQL
• TiDB

Disallow changing column order

Changing column order may cause performance issues. Users should be cautious about this.

How the rule works

Bytebase checks if changing column order.

Specifically, Bytebase checks:

• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Use integer for auto-increment columns

The auto-increment column must be integer.

How the rule works

Bytebase checks the auto-increment column type.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Disallow set charset for columns

It's better to set the charset in the table or database.

How the rule works

Bytebase checks if setting charset for columns.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Set unsigned attribute on auto-increment columns

Setting unsigned attribute on auto-increment columns to avoid negative numbers.

How the rule works

Bytebase checks the unsigned attribute for auto-increment columns.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Column comment convention

Configure whether the column requires comments and the maximum comment length.

How the rule works

Bytebase checks the column comment.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Maximum CHAR length

The CHAR type is the fixed-length type. A longer CHAR will require more storage space.

How the rule works

Bytebase checks the length for the CHAR type.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Auto-increment initial value

Set initial value for auto-increment columns.

How the rule works

Bytebase checks the initial value for auto-increment columns.

Specifically, Bytebase checks:

• CREATE TABLE statements

Support database engine

• MySQL
• TiDB

Limit the count of current time columns

Limit the count of NOW(), CURRENT_TIME() and CURRENT_TIMESTAMP() columns.

How the rule works

This rule will count the two types of the columns:

1. the column with default current time , such as DEFAULT NOW()
2. the column with ON UPDATE current time, such as ON UPDATE NOW()

If the count of type one columns is more than two or the count of type two columns is more than one, this rule will alert users.

The meaning of the number is:

1. A table usually has created_ts and updated_ts column with DEFAULT NOW().
2. A table usually has updated_ts column with ON UPDATE NOW()

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Require column default value

Require default value for all columns, except PRIMARY KEY, JSON, BLOB, TEXT, GEOMETRY, AUTO_INCREMENT, GENERATED columns.

How the rule works

Bytebase checks the column default value.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Index

Disallow duplicate column in index keys

How the rule works

Bytebase checks if there exists duplicate column in index keys.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Limit the count of index keys

Limit the count of index keys in one index.

How the rule works

Bytebase checks the count of index keys in each index.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Limit key type for primary keys

Alert users if key type is not INT or BIGINT in primary keys.

How the rule works

Bytebase checks the key type for primary keys.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Disallow BLOB and TEXT for index keys

Disallow using BLOB and TEXT type as index keys.

How the rule works

Bytebase checks the key type for index keys.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

Index count limit

Limit the index count in one table.

How the rule works

Bytebase checks the index count for each table.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements
• CREATE INDEX statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Primary key type allowlist

Limit the data type for primary key.

How the rule works

Bytebase checks the data type for each primary key.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE ADD CONSTRAINT statements

Support database engine

• PostgreSQL

Create index concurrently

Creating indexes blocks writes (but not reads) on the table until it's done. Use CONCURRENTLY when creates indexes can allow writes to continue.

How the rule works

Specifically, Bytebase checks:

• CREATE INDEX statements

Support database engine

• PostgreSQL

Database

Drop database restriction

Can only drop the database if there's no table in it. It requires users to drop all containing tables first before dropping the database.

How the rule works

Bytebase checks if there exists any table in the specific database.

Specifically, Bytebase checks:

• DROP DATABASE statements

Support database engine

• MySQL
• TiDB

Support for PostgreSQL is coming soon.

System

Charset allow list

How the rule works

Bytebase checks if the SQL statement uses the charset outside of the allow list.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Collation allow list

How the rule works

Bytebase checks if the SQL statement uses the collation outside of the allow list.

Specifically, Bytebase checks:

• CREATE TABLE statements
• ALTER TABLE statements

Support database engine

• MySQL
• TiDB
• PostgreSQL

Comment length limit

How the rule works

Bytebase checks all COMMENT ON statements.

Support database engine

• PostgreSQL