无需编程，基于甲骨文 oracle 数据库零代码生成 CRUD 增删改查 RESTful API 接口

回顾

通过之前一篇文章 无需编程，基于 PostgreSQL 零代码生成 CRUD 增删改查 RESTful API 接口 的介绍，采纳形象工厂设计模式，曾经反对了大象数据库 PostgreSQL。之前通过字符串拼接生成 DDL SQL 语句，比拟繁琐。本文开始，引入了 FreeMarker 模版引擎，通过配置模版实现创立和批改物理表构造 SQL 语句，简化了大量代码，进步了效率，并且通过配置 oracle 数据库 SQL 模版，基于 oracle 数据库，零代码实现 crud 增删改查。

FreeMarker 简介

FreeMarker 是一款模板引擎：即一种基于模板和要扭转的数据，并用来生成输入文本 (HTML 网页，电子邮件，配置文件，源代码等) 的通用工具。它不是面向最终用户的，而是一个 Java 类库，是一款程序员能够嵌入他们所开发产品的组件。模板编写为 FreeMarker Template Language (FTL)。它是简略的，专用的语言，不是像 PHP 那样成熟的编程语言。那就意味着要筹备数据在实在编程语言中来显示，比方数据库查问和业务运算，之后模板显示曾经筹备好的数据。在模板中，你能够专一于如何展示数据，而在模板之外能够专一于要展现什么数据。

UI 界面

通过产品对象为例，无需编程，基于 Oracle 数据库，通过配置零代码实现 CRUD 增删改查 RESTful API 接口和治理 UI。

创立产品

编辑产品数据

产品数据列表

通过 Oracle SQL Developer 查问 Oracle 数据

定义元数据对象模型

元数据表 ca_meta_table

元数据表 ca_meta_table，用于记录表的根本信息。

TableEntity 对象

TableEntity 为“元数据表”对象，和 ca_meta_table 字段对应

public class TableEntity {
    private Long id;

    private String name;

    private String caption;

    private String description;

    private Timestamp createdDate;

    private Timestamp lastModifiedDate;

    private String pluralName;

    private String tableName;

    private EngineEnum engine;

    private Boolean createPhysicalTable;

    private Boolean reverse;

    private Boolean systemable;

    private Boolean readOnly;

    private List<ColumnEntity> columnEntityList;

    private List<IndexEntity> indexEntityList;
}

元数据列 ca_meta_column

元数据列 ca_meta_column，用于记录表字段信息，比方类型，长度，默认值等。

ColumnEntity 对象

ColumnEntity 为“元数据列”对象，和 ca_meta_column 字段对应

public class ColumnEntity {
  private Long id;

  private String name;

  private String caption;

  private String description;

  private Timestamp createdDate;

  private Timestamp lastModifiedDate;

  private Integer displayOrder;

  private DataTypeEnum dataType;

  private IndexTypeEnum indexType;

  private IndexStorageEnum indexStorage;

  private String indexName;

  private Integer length;

  private Integer precision;

  private Integer scale;

  private String defaultValue;

  private Long seqId;

  private Boolean unsigned;

  private Boolean autoIncrement;

  private Boolean nullable;

  private Boolean insertable;

  private Boolean updatable;

  private Boolean queryable;

  private Boolean displayable;

  private Boolean systemable;

  private Long tableId;
}

元数据索引 ca_meta_index

元数据索引 ca_meta_index，用于记录表联结索引信息，比方索引类型，名称等。

IndexEntity 对象

IndexEntity 为“元数据索引”对象，和 ca_meta_index 字段对应

public class IndexEntity {
  private Long id;

  private String name;

  private String caption;

  private String description;

  private Timestamp createdDate;

  private Timestamp lastModifiedDate;

  private IndexTypeEnum indexType;

  private IndexStorageEnum indexStorage;

  private Long tableId;

  private List<IndexLineEntity> indexLineEntityList;
}

元数据索引行 ca_meta_index_line

元数据索引行 ca_meta_index_line，用于记录表联结索引行信息，一个联结索引能够对应多个联结索引行，示意由多个字段组成。

IndexLineEntity 对象

IndexLineEntity“元数据索行”对象，和 ca_meta_index_line 字段对应

public class IndexLineEntity {
  private Long id;

  private Long columnId;

  private ColumnEntity columnEntity;

  private Long indexId;
}

定义 FreeMarker 模版

创立表 create-table.sql.ftl

CREATE TABLE "${tableName}" (
<#list columnEntityList as columnEntity>
  <#if columnEntity.dataType == "BOOL">
    "${columnEntity.name}" NUMBER(1)<#if columnEntity.defaultValue??> DEFAULT <#if columnEntity.defaultValue == "true">1<#else>0</#if></#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "INT">
    "${columnEntity.name}" INT<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity.indexType?? && columnEntity.indexType == "PRIMARY"> PRIMARY KEY</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "BIGINT">
    "${columnEntity.name}" INT<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity.indexType?? && columnEntity.indexType == "PRIMARY"> PRIMARY KEY</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "FLOAT">
    "${columnEntity.name}" FLOAT<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "DOUBLE">
    "${columnEntity.name}" REAL<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "DECIMAL">
    "${columnEntity.name}" DECIMAL<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "DATE">
    "${columnEntity.name}" DATE<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "TIME">
    "${columnEntity.name}" CHAR(8)<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "DATETIME">
    "${columnEntity.name}" DATE<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "TIMESTAMP">
    "${columnEntity.name}" TIMESTAMP<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "CHAR">
    "${columnEntity.name}" CHAR(${columnEntity.length})<#if columnEntity.defaultValue??> DEFAULT '${columnEntity.defaultValue}'</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity.indexType?? && columnEntity.indexType == "PRIMARY"> PRIMARY KEY</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "VARCHAR">
    "${columnEntity.name}" VARCHAR(${columnEntity.length})<#if columnEntity.defaultValue??> DEFAULT '${columnEntity.defaultValue}'</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity.indexType?? && columnEntity.indexType == "PRIMARY"> PRIMARY KEY</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "PASSWORD">
    "${columnEntity.name}" VARCHAR(200)<#if columnEntity.defaultValue??> DEFAULT '${columnEntity.defaultValue}'</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "ATTACHMENT">
    "${columnEntity.name}" VARCHAR(4000)<#if columnEntity.defaultValue??> DEFAULT '${columnEntity.defaultValue}'</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "TEXT">
    "${columnEntity.name}" VARCHAR(4000)<#if columnEntity.defaultValue??> DEFAULT '${columnEntity.defaultValue}'</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "LONGTEXT">
    "${columnEntity.name}" LONG<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "BLOB">
    "${columnEntity.name}" BLOB<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#elseif columnEntity.dataType == "LONGBLOB">
    "${columnEntity.name}" BLOB<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity_has_next>,</#if>
  <#else>
    "${columnEntity.name}" VARCHAR(200)<#if columnEntity.defaultValue??> DEFAULT ${columnEntity.defaultValue}</#if><#if columnEntity.nullable != true> NOT NULL</#if><#if columnEntity.indexType?? && columnEntity.indexType == "PRIMARY"> PRIMARY KEY</#if><#if columnEntity_has_next>,</#if>
  </#if>
</#list>
);

<#list columnEntityList as columnEntity>
  <#if columnEntity.indexType?? && columnEntity.indexType == "UNIQUE">
    ALTER TABLE "${tableName}" ADD CONSTRAINT "${columnEntity.indexName}" UNIQUE("${columnEntity.name}");
  </#if>

  <#if columnEntity.indexType?? && (columnEntity.indexType == "INDEX" || columnEntity.indexType == "FULLTEXT")>
    CREATE INDEX "${columnEntity.indexName}" ON "${tableName}" ("${columnEntity.name}");
  </#if>
</#list>

<#if indexEntityList??>
  <#list indexEntityList as indexEntity>
    <#if indexEntity.indexType?? && indexEntity.indexType == "UNIQUE">
      ALTER TABLE "${tableName}" ADD CONSTRAINT "${indexEntity.name}" UNIQUE(<#list indexEntity.indexLineEntityList as indexLineEntity>"${indexLineEntity.columnEntity.name}"<#if indexLineEntity_has_next>,</#if></#list>);
    </#if>

    <#if indexEntity.indexType?? && (indexEntity.indexType == "INDEX" || indexEntity.indexType == "FULLTEXT")>
      CREATE INDEX "${indexEntity.name}" ON "${tableName}" (<#list indexEntity.indexLineEntityList as indexLineEntity>"${indexLineEntity.columnEntity.name}"<#if indexLineEntity_has_next>,</#if></#list>);
    </#if>
  </#list>
</#if>

COMMENT ON TABLE "${tableName}" IS '${caption}';

<#list columnEntityList as columnEntity>
  COMMENT ON COLUMN "${tableName}"."${columnEntity.name}" IS '${columnEntity.caption}';
</#list>

模版解析 SQL

首先保留元数据信息，下一步传递模版名称和元数据 model，动静解析成创立表 SQL 语句，而后创立物理表，这样元数据和物理表就关联上了。运行时通过解析元数据动静生成 insert，select，update，delete 等 SQL 语句，零代码实现业务数据 crud 性能。

public String processTemplateToString(String database, String templateName, Object dataModel) {
    String str = null;
    StringWriter stringWriter = new StringWriter();
    try {Configuration config = new Configuration(Configuration.VERSION_2_3_31);
        config.setNumberFormat("#");
        String templateValue = getTemplate(database, templateName);
        if (templateValue == null) {return str;}

        Template template = new Template(templateName, templateValue, config);
        template.process(dataModel, stringWriter);

        str = stringWriter.getBuffer().toString().trim();
        log.info(str);
    } catch (Exception e) {e.printStackTrace();
        throw new BusinessException(ApiErrorCode.DEFAULT_ERROR, e.getMessage());
    }

    return str;
}

public List<String> toCreateTableSql(TableEntity tableEntity) {String createTableSql = processTemplateToString("create-table.sql.ftl", tableEntity);

  if (createTableSql == null) {throw new BusinessException(ApiErrorCode.DEFAULT_ERROR, "create-table.sql is empty!");
  }

  List<String> sqls = new ArrayList<String>();
  String[] subSqls = createTableSql.split(";");
  for (String t : subSqls) {String subSql = t.trim();
    if (!subSql.isEmpty()) {sqls.add(t);
    }
  }

  return sqls;
}

public Long create(TableDTO tableDTO) {TableEntity tableEntity = tableMapper.toEntity(tableDTO);
  //TODO
  Long tableId = crudService.create(TABLE_TABLE_NAME, tableEntity);
  List<String> sqlList = crudService.toCreateTableSql(tableEntity);
  for (String sql: sqlList) {execute(sql);
  }
  //TODO
  return tableId;
}

批改表

包含表构造和索引的批改，删除等，和创立表原理相似。

application.properties

须要依据须要配置数据库连贯驱动，无需从新公布，就能够切换不同的数据库。

#oracle
spring.datasource.url=jdbc:oracle:thin:@//localhost:1521/XEPDB1
spring.datasource.driverClassName=oracle.jdbc.OracleDriver
spring.datasource.username=crudapi
spring.datasource.password=crudapi
spring.datasource.initialization-mode=always
spring.datasource.schema=classpath:schema.sql

小结

本文次要介绍了 crudapi 反对 oracle 数据库实现原理，并且以产品对象为例，零代码实现了 CRUD 增删改查 RESTful API，后续介绍更多的数据库，比方 MSSQL Server，Mongodb 等。

综上所述，利用 crudapi 零碎能够极大地提高工作效率和节约老本，让数据处理变得更简略！

crudapi 简介

crudapi 是 crud+api 组合，示意增删改查接口，是一款零代码可配置的产品。应用 crudapi 能够辞别枯燥无味的增删改查代码，让您更加专一业务，节约大量老本，从而进步工作效率。
crudapi 的指标是让解决数据变得更简略，所有人都能够收费应用！
无需编程，通过配置主动生成 crud 增删改查 RESTful API，提供后盾 UI 治理业务数据。基于支流的开源框架，领有自主知识产权，反对二次开发。

demo 演示

crudapi 属于产品级的零代码平台，不同于主动代码生成器，不须要生成 Controller、Service、Repository、Entity 等业务代码，程序运行起来就能够应用，真正 0 代码，能够笼罩根本的和业务无关的 CRUD RESTful API。

官网地址：https://crudapi.cn
测试地址：https://demo.crudapi.cn/crudapi/login

附源码地址

GitHub 地址

https://github.com/crudapi/crudapi-admin-web

Gitee 地址

https://gitee.com/crudapi/crudapi-admin-web

因为网络起因，GitHub 可能速度慢，改成拜访 Gitee 即可，代码同步更新。