{"id":17447,"date":"2024-03-15T15:01:30","date_gmt":"2024-03-15T15:01:30","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/"},"modified":"2024-03-21T10:55:46","modified_gmt":"2024-03-21T10:55:46","slug":"how-can-multiple-tables-be-queried-together-in-spring-boot","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/","title":{"rendered":"How can multiple tables be queried together in Spring Boot?"},"content":{"rendered":"<p>In Spring Boot, you can perform multi-table queries using JPA (Java Persistence API) and Hibernate.<\/p>\n<p>Here is a common method for performing a multiple table join:<\/p>\n<ol>\n<li>Create entity classes: First, create entity classes corresponding to each table, and use annotations to map them to the tables in the database.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-meta\">@Entity<\/span>\r\n<span class=\"hljs-meta\">@Table(name = \"table1\")<\/span>\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Table1<\/span> {\r\n    <span class=\"hljs-meta\">@Id<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Long id;\r\n    <span class=\"hljs-keyword\">private<\/span> String name;\r\n    <span class=\"hljs-comment\">\/\/ getters and setters<\/span>\r\n}\r\n\r\n<span class=\"hljs-meta\">@Entity<\/span>\r\n<span class=\"hljs-meta\">@Table(name = \"table2\")<\/span>\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Table2<\/span> {\r\n    <span class=\"hljs-meta\">@Id<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Long id;\r\n    <span class=\"hljs-keyword\">private<\/span> String description;\r\n    <span class=\"hljs-comment\">\/\/ getters and setters<\/span>\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Mapping between two entities in a one-to-one relationship.<\/li>\n<li>&#8211; One-to-Many<\/li>\n<li>Used to define a many-to-one relationship in a database mapping.<\/li>\n<li>A relationship where each instance of one entity can be associated with multiple instances of another entity.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-meta\">@Entity<\/span>\r\n<span class=\"hljs-meta\">@Table(name = \"table1\")<\/span>\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Table1<\/span> {\r\n    <span class=\"hljs-meta\">@Id<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Long id;\r\n    <span class=\"hljs-keyword\">private<\/span> String name;\r\n\r\n    <span class=\"hljs-meta\">@OneToOne(mappedBy = \"table1\")<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Table2 table2;\r\n    \r\n    <span class=\"hljs-comment\">\/\/ getters and setters<\/span>\r\n}\r\n\r\n<span class=\"hljs-meta\">@Entity<\/span>\r\n<span class=\"hljs-meta\">@Table(name = \"table2\")<\/span>\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">Table2<\/span> {\r\n    <span class=\"hljs-meta\">@Id<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Long id;\r\n    \r\n    <span class=\"hljs-meta\">@OneToOne<\/span>\r\n    <span class=\"hljs-meta\">@JoinColumn(name = \"table1_id\")<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Table1 table1;\r\n\r\n    <span class=\"hljs-comment\">\/\/ getters and setters<\/span>\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>A repository for handling basic CRUD operations.<\/li>\n<li>A repository that provides methods for easy interaction with a database in a Spring application is referred to as JpaRepository.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">interface<\/span> <span class=\"hljs-title class_\">Table1Repository<\/span> <span class=\"hljs-keyword\">extends<\/span> <span class=\"hljs-title class_\">JpaRepository<\/span>&lt;Table1, Long&gt; {\r\n}\r\n\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">interface<\/span> <span class=\"hljs-title class_\">Table2Repository<\/span> <span class=\"hljs-keyword\">extends<\/span> <span class=\"hljs-title class_\">JpaRepository<\/span>&lt;Table2, Long&gt; {\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Performing multi-table queries: In the business logic layer or service layer, you can use JPA&#8217;s query methods as needed to perform multi-table queries.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-meta\">@Service<\/span>\r\n<span class=\"hljs-keyword\">public<\/span> <span class=\"hljs-keyword\">class<\/span> <span class=\"hljs-title class_\">MyService<\/span> {\r\n    <span class=\"hljs-meta\">@Autowired<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Table1Repository table1Repository;\r\n    \r\n    <span class=\"hljs-meta\">@Autowired<\/span>\r\n    <span class=\"hljs-keyword\">private<\/span> Table2Repository table2Repository;\r\n    \r\n    <span class=\"hljs-keyword\">public<\/span> List&lt;Table1&gt; <span class=\"hljs-title function_\">getTable1WithTable2<\/span><span class=\"hljs-params\">()<\/span> {\r\n        <span class=\"hljs-keyword\">return<\/span> table1Repository.findAll();  <span class=\"hljs-comment\">\/\/ \u8fd4\u56de\u6240\u6709Table1\uff0c\u5e76\u81ea\u52a8\u8054\u67e5\u5173\u8054\u7684Table2<\/span>\r\n    }\r\n}\r\n<\/code><\/pre>\n<p>The above method can conveniently perform multi-table queries. Additionally, more complex multi-table queries can also be achieved using native SQL queries, JPQL queries, and other methods.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In Spring Boot, you can perform multi-table queries using JPA (Java Persistence API) and Hibernate. Here is a common method for performing a multiple table join: Create entity classes: First, create entity classes corresponding to each table, and use annotations to map them to the tables in the database. @Entity @Table(name = &#8220;table1&#8221;) public class [&hellip;]<\/p>\n","protected":false},"author":14,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-17447","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How can multiple tables be queried together in Spring Boot? - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How can multiple tables be queried together in Spring Boot?\" \/>\n<meta property=\"og:description\" content=\"In Spring Boot, you can perform multi-table queries using JPA (Java Persistence API) and Hibernate. Here is a common method for performing a multiple table join: Create entity classes: First, create entity classes corresponding to each table, and use annotations to map them to the tables in the database. @Entity @Table(name = &quot;table1&quot;) public class [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/SiliCloudGlobal\/\" \/>\n<meta property=\"article:published_time\" content=\"2024-03-15T15:01:30+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-03-21T10:55:46+00:00\" \/>\n<meta name=\"author\" content=\"Noah Thompson\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:site\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Noah Thompson\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\"},\"author\":{\"name\":\"Noah Thompson\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/#\/schema\/person\/2e83cc6ab9f60d36921c2d0f9f280f4a\"},\"headline\":\"How can multiple tables be queried together in Spring Boot?\",\"datePublished\":\"2024-03-15T15:01:30+00:00\",\"dateModified\":\"2024-03-21T10:55:46+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\"},\"wordCount\":173,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/#organization\"},\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\",\"url\":\"https:\/\/www.silicloud.com\/blog\/how-can-multiple-tables-be-queried-together-in-spring-boot\/\",\"name\":\"How can multiple tables be queried together in Spring Boot? 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