Column Constraints

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Column Constraints
A TableIndex can be created directly from a Blueprint or from a existing Column. The TableIndex includes methods for further configuring the index which is required when defining foreign keys.
references
Set the referencing column for a foreign key relationship. For example, id for a country_id column.
Argument
Type
Required
Default
Description
columns
any
true
​
A column or array of columns that represents the foreign key reference.
Example:
SchemaBuilder
1
schema.create( "users", function( table ) {
2
    table.unsignedInteger( "country_id" ).references( "id" ).onTable( "countries" );
3
} );
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SQL (MySQL)
1
CREATE TABLE `users` (
2
    `country_id` INTEGER UNSIGNED NOT NULL,
3
    CONSTRAINT `fk_users_country_id` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON UPDATE NO ACTION ON DELETE NO ACTION
4
)
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onTable
Sets the referencing table for a foreign key relationship. For example, countries for a country_id column.
Argument
Type
Required
Default
Description
table
string
true
​
The referencing table name.
Example:
SchemaBuilder
1
schema.create( "users", function( table ) {
2
    table.unsignedInteger( "country_id" ).references( "id" ).onTable( "countries" );
3
} );
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SQL (MySQL)
1
CREATE TABLE `users` (
2
    `country_id` INTEGER UNSIGNED NOT NULL,
3
    CONSTRAINT `fk_users_country_id` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON UPDATE NO ACTION ON DELETE NO ACTION
4
)
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onUpdate
Set the strategy for updating foreign keys when the parent key is updated.
Argument
Type
Required
Default
Description
option
string
true
​
The strategy to use. Available values are: RESTRICT, CASCADE, SET NULL, NO ACTION, SET DEFAULT
Example:
SchemaBuilder
1
schema.create( "users", function( table ) {
2
    table.unsignedInteger( "country_id" )
3
        .references( "id" )
4
        .onTable( "countries" )
5
        .onUpdate( "CASCADE" );
6
} );
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SQL (MySQL)
1
CREATE TABLE `users` (
2
    `country_id` INTEGER UNSIGNED NOT NULL,
3
    CONSTRAINT `fk_users_country_id` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON UPDATE CASCADE ON DELETE NO ACTION
4
)
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onDelete
Set the strategy for updating foreign keys when the parent key is deleted.
Argument
Type
Required
Default
Description
option
string
true
​
The strategy to use. Available values are: RESTRICT, CASCADE, SET NULL, NO ACTION, SET DEFAULT
Example:
SchemaBuilder
1
schema.create( "users", function( table ) {
2
    table.unsignedInteger( "country_id" )
3
        .references( "id" )
4
        .onTable( "countries" )
5
        .onDelete( "SET NULL" );
6
} );
Copied!
SQL (MySQL)
1
CREATE TABLE `users` (
2
    `country_id` INTEGER UNSIGNED NOT NULL,
3
    CONSTRAINT `fk_users_country_id` FOREIGN KEY (`country_id`) REFERENCES `countries` (`id`) ON UPDATE NO ACTION ON DELETE SET NULL
4
)
Copied!
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Column Modifiers
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Creating Table Constraints
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