Enumeration

SQLTableConstraintAlgorithm

Table-level data constraints.

enum SQLTableConstraintAlgorithm

Overview

Most dialects of SQL support both column-level (specific to a single column) and table-level (applicable to a list of one or more columns within the table) constraints. While some constraints can be expressed either way, others are only allowed at the column level. See SQLColumnConstraintAlgorithm for column-level constraints.

Most table-level constraints can optionally be explicitly named; see SQLConstraint for this functionality.

Table constraints are used by SQLCreateTable and SQLAlterTable, and also appear directly in the APIs of SQLAlterTableBuilder, SQLCreateIndexBuilder, and SQLCreateTableBuilder.

Topics

Enumeration Cases

SQLTableConstraintAlgorithm.check(_:)
A CHECK constraint and its associated validation expression.
SQLTableConstraintAlgorithm.foreignKey(columns:references:)
A FOREIGN KEY constraint over one or more columns, specifying the referenced data.
SQLTableConstraintAlgorithm.primaryKey(columns:)
A PRIMARY KEY constraint over one or more columns.
SQLTableConstraintAlgorithm.unique(columns:)
A UNIQUE value constraint, also called a unique key, over one or more columns.

Instance Methods

serialize(to:)
Invoked when a request is made to serialize the expression to raw SQL.

Relationships

Conforms To

SQLExpression
Swift.Sendable
Swift.SendableMetatype

SQLAlterColumnDefinitionType
A clause specifying a new data type to be applied to an existing column.
SQLColumnAssignment
Encapsulates a column_name=value expression in the context of an UPDATE query’s value assignment list. This is distinct from an SQLBinaryExpression using the .equal operator in that the left side must be an unqualified column name, the operator must be =, and the right side may use SQLExcludedColumn when the assignment appears in the assignments list of a SQLConflictAction.update(assignments:predicate:) specification.
SQLColumnConstraintAlgorithm
Column-level data constraints.
SQLColumnDefinition
A clause expressing a column definition, for use when creating and altering tables.
SQLConflictAction
An action to take when an INSERT query encounters a unique constraint violation.
SQLConflictResolutionStrategy
Specifies a conflict resolution strategy and associated conditions for an INSERT query. An INSERT with a conflict strategy is often refered to as an UPSERT (“insert or update”). Databases are not required to support any given subset of upsert functionality, or any at all.
SQLDropBehavior
Specifies a behavior when performing a DROP operation on a database object which is referenced by other objects.
SQLEnumDataType
Represents a data type which specifies an enumeration in the database.
SQLExcludedColumn
An expression appearing on the right side of a column assignment which, when the assignment list is part of an upsert’s update acion, refers to the value which was originally to be inserted for the given column.
SQLForeignKey
A complete FOREIGN KEY constraint specification.
SQLInsertModifier
Simple helper for working around MySQL’s refusal to implement standard SQL. Only emits SQL when needed.
SQLJoin
Encapsulates a single SQL JOIN, specifying the join type, the right-side table, and condition.
SQLJoinMethod
The method used by a table join clause.
SQLLockingClause
An SQL locking clause.
SQLOrderBy
A pair of expressions, one describing a query sort key and the other a directionality for that key.