Package com.healthmarketscience.sqlbuilder.custom

SqlBuilder supports two types of custom SQL: Custom values/expressions within existing queries - this type of customization can be achieved using the custom SqlObject variants: CustomSql, CustomExpression, and CustomCondition. Custom clauses added to existing queries - the classes in this package (and subpackages) enable this type of customization, read on for details.

See: Description

Interface Summary

Interface	Description
HookAnchor	Marker interface for the custom hook anchors use by specific SqlObjects.

Class Summary

Class	Description
CustomSyntax	Utility base class for custom SQL syntax instances.
NamedParamObject	SqlObject expression which inserts a "named" parameter like ":<name>".

Enum Summary

Enum	Description
HookType	Enum defining the type of customization relative to the HookAnchor (which is typically a sub-clause within a query).

Package com.healthmarketscience.sqlbuilder.custom Description

SqlBuilder supports two types of custom SQL:

• Custom values/expressions within existing queries - this type of customization can be achieved using the custom SqlObject variants: CustomSql, CustomExpression, and CustomCondition.
• Custom clauses added to existing queries - the classes in this package (and subpackages) enable this type of customization, read on for details.

Custom SQL Syntax

Inserting custom SQL syntax into queries involves a few different pieces all working together.

• A query (or other existing SqlObject type) which has enabled custom SQL syntax support (e.g. SelectQuery). This is done via a nested Hook enum which defines the "hook anchors" for that type (e.g. SelectQuery.Hook).
• A "hook anchor" (an enum which implements the HookAnchor marker interface) defines locations within the related query in which custom SQL syntax can be inserted. Custom SQL syntax generally falls into one of two categories: additional keywords which enhance an existing clause or additional sub-clauses within a query. In both cases, the custom syntax needs to be inserted into the correct location within the query and the "hook anchor" provides the first of two important bits of location information.
• The HookType is the second bit of important information which ties the custom SQL syntax to the correct location in the query. It defines how the custom syntax should be inserted relative to the "hook anchor".
• The actual custom SQL syntax object. For convenience, the custom syntax implementation may extend CustomSyntax, but that is not a requirement. CustomSyntax based implementations know how to insert themselves into the correct location in relevant queries so they can easily be added to a query using the simplified addCustomization() method (e.g. SelectQuery.addCustomization(CustomSyntax)). However, any ad hoc custom syntax can be added to customizable queries by specifying the HookType and "hook anchor" when adding (e.g. SelectQuery.addCustomization(Hook,HookType,Object))

Supported Customizations

SqlBuilder currently has existing constructs for few common database specific customizations:

• Oracle com.healthmarketscience.sqlbuilder.custom.oracle
• MySQL com.healthmarketscience.sqlbuilder.custom.mysql
• PostreSQL com.healthmarketscience.sqlbuilder.custom.postgresql
• SQL Server com.healthmarketscience.sqlbuilder.custom.sqlserver

Customizable Queries

Only a few SqlBuilder queryies are currently customizable:

• SelectQuery
• CreateTableQuery
• CreateIndexQuery