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SQL rendering
Applies to ✅ Open Source Edition ✅ Express Edition ✅ Professional Edition ✅ Enterprise Edition
Every org.jooq.QueryPart must implement the accept(Context) method to render its SQL string to a org.jooq.RenderContext. This RenderContext has two purposes:
- It provides some information about the "state" of SQL rendering.
- It provides a common API for constructing SQL strings on the context's internal
java.lang.StringBuilder
An overview of the org.jooq.RenderContext API is given here:
// These methods are useful for generating unique aliases within a RenderContext (and thus within a Query) String peekAlias(); String nextAlias(); // These methods return rendered SQL String render(); String render(QueryPart part); // These methods allow for fluent appending of SQL to the RenderContext's internal StringBuilder RenderContext keyword(String keyword); RenderContext literal(String literal); RenderContext sql(String sql); RenderContext sql(char sql); RenderContext sql(int sql); RenderContext sql(QueryPart part); // These methods allow for controlling formatting of SQL, if the relevant Setting is active RenderContext formatNewLine(); RenderContext formatSeparator(); RenderContext formatIndentStart(); RenderContext formatIndentStart(int indent); RenderContext formatIndentLockStart(); RenderContext formatIndentEnd(); RenderContext formatIndentEnd(int indent); RenderContext formatIndentLockEnd(); // These methods control the RenderContext's internal state boolean inline(); RenderContext inline(boolean inline); boolean qualify(); RenderContext qualify(boolean qualify); boolean namedParams(); RenderContext namedParams(boolean renderNamedParams); CastMode castMode(); RenderContext castMode(CastMode mode); Boolean cast(); RenderContext castModeSome(SQLDialect... dialects);
The following additional methods are inherited from a common org.jooq.Context, which is shared among org.jooq.RenderContext and org.jooq.BindContext:
// These methods indicate whether fields or tables are being declared (MY_TABLE AS MY_ALIAS) or referenced (MY_ALIAS) boolean declareFields(); Context declareFields(boolean declareFields); boolean declareTables(); Context declareTables(boolean declareTables); // These methods indicate whether a top-level query is being rendered, or a subquery boolean subquery(); Context subquery(boolean subquery); // These methods provide the bind value indices within the scope of the whole Context (and thus of the whole Query) int nextIndex(); int peekIndex();
An example of rendering SQL
A simple example can be provided by checking out jOOQ's internal representation of a (simplified) CompareCondition. It is used for any org.jooq.Condition comparing two fields as for example the AUTHOR.ID = BOOK.AUTHOR_ID condition here:
-- [...] FROM AUTHOR JOIN BOOK ON AUTHOR.ID = BOOK.AUTHOR_ID -- [...]
This is how jOOQ renders such a condition (simplified example):
@Override
public final void accept(Context<?> context) {
// The CompareCondition delegates rendering of the Fields to the Fields
// themselves and connects them using the Condition's comparator operator:
context.visit(field1)
.sql(" ")
.keyword(comparator.toSQL())
.sql(" ")
.visit(field2);
}
See the manual's sections about custom QueryParts and plain SQL QueryParts to learn about how to write your own query parts in order to extend jOOQ.
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