org.jooq.SQL Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
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* https://www.apache.org/licenses/LICENSE-2.0
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* distributed under the License is distributed on an "AS IS" BASIS,
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* -----------------------------------------------------------------------------
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* database integrations.
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package org.jooq;
import org.jooq.conf.ParamType;
import org.jooq.conf.StatementType;
import org.jooq.impl.DSL;
/**
* A plain SQL {@link QueryPart}.
*
* Plain SQL query parts can be constructed in a variety of ways from the
* {@link DSL} API ({@link DSL#field(String)}, {@link DSL#table(String)}, etc.)
* as well as from convenience methods such as for instance
* {@link SelectWhereStep#where(String)}. These query parts allow for embedding
* simple SQL strings with associated bind variables or nested queryparts.
*
*
Template language
*
* A simple template language is implemented by such plain SQL query parts,
* exposing the following features:
*
* - Nested query parts: A template may refer to argument
* query parts using zero-based, numbered references wrapped in curly braces.
* The following expression will embed
expr1 and expr2
* at the appropriate locations:
*
*
* DSL.field("GROUP_CONCAT(DISTINCT {0} ORDER BY {1} ASC SEPARATOR '-')", expr1, expr2);
*
Query part indexes may be referenced multiple times from within
* a template.
* - Keywords: Curly braces are also used to delimit
* keywords, which expose the behaviour specified in {@link DSL#keyword(String)}
* (e.g. upper-casing, lower-casing, etc.) . The following expression makes use
* of embedded keywords in a plain SQL template:
*
*
DSL.field("{current_timestamp}");
* - JDBC escape syntax: JDBC also allows for using curly
* braces to embed escape expressions in SQL statements, such as date literals,
* for instance. JDBC escape syntax is left untouched by jOOQ's plain SQL query
* part renderings. The following example shows such usage:
*
*
DSL.field("{d '2015-01-01'}");
The following JDBC
* escape syntax elements are recognised:
*
* {d [date literal]}{t [time literal]}{ts [timestamp literal]}{fn [function literal]}
*
* - JDBC bind variables: in case bind variables should be
* inlined (as in {@link DSL#inline(CharSequence)}, {@link ParamType#INLINED},
* or {@link StatementType#STATIC_STATEMENT}), plain SQL query parts will
* discover question marks (
?) and named parameters
* (:identifier) at syntactically appropriate positions, e.g.
* outside of comments, string literals, quoted name literals, and substitute
* the appropriate bind value into the template.
*
*
* Instances can be created using {@link DSL#sql(String)} and overloads.
*
* @author Lukas Eder
*/
@PlainSQL
public interface SQL extends QueryPart {
}