基于Vue和Quasar的前端SPA项目实战之数据库逆向（十二）
回顾
通过之前文章 基于Vue和Quasar的前端SPA项目实战之动态表单（五）的介绍，实现了动态表单功能。如果是全新的项目，通过配置元数据并且创建物理表，从而自动实现业务数据的CRUD增删改查。但是如果数据库表已经存在的情况下，如何通过配置表单元数据进行管理呢？这时候数据库逆向功能就很有必要了。
简介
数据库逆向就是通过读取数据库物理表schema信息，然后生成表单元数据，可以看成“dbfirst”模式，即先有数据库表，然后根据表生成元数据，逆向表单后续操作和普通动态表单类似。
UI界面
输入物理表名称，启用“数据库逆向”功能，然后点击“加载元数据”，然后会自动填充表单字段相关元数据信息。
数据表准备
以ca_product产品为例，通过phpmyadmin创建表
创建产品表
CREATE TABLE `ca_product` (
`id` bigint UNSIGNED NOT NULL COMMENT '编号',
`name` varchar(200) COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '名称',
`fullTextBody` text COLLATE utf8mb4_unicode_ci COMMENT '全文索引',
`createdDate` datetime NOT NULL COMMENT '创建时间',
`lastModifiedDate` datetime DEFAULT NULL COMMENT '修改时间',
`code` varchar(200) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '编码',
`brand` varchar(200) COLLATE utf8mb4_unicode_ci DEFAULT NULL COMMENT '品牌',
`price` decimal(10,0) DEFAULT NULL COMMENT '单价',
`weight` decimal(10,0) DEFAULT NULL COMMENT '重量',
`length` decimal(10,0) DEFAULT NULL COMMENT '长',
`width` decimal(10,0) DEFAULT NULL COMMENT '宽',
`high` decimal(10,0) DEFAULT NULL COMMENT '高',
`ats` bigint DEFAULT NULL COMMENT '库存个数'
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='产品';
ALTER TABLE `ca_product`
ADD PRIMARY KEY (`id`),
ADD UNIQUE KEY `UQ_CODE` (`code`) USING BTREE;
ALTER TABLE `ca_product` ADD FULLTEXT KEY `ft_fulltext_body` (`fullTextBody`);
ALTER TABLE `ca_product`
MODIFY `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT COMMENT '编号', AUTO_INCREMENT=1;
COMMIT;
查询schema
mysql数据库通过如下SQL语句可以查询表单、字段、索引等信息
SHOW TABLE STATUS LIKE TABLE_NAME
SHOW FULL COLUMNS FROM TABLE_NAME
SHOW INDEX FROM TABLE_NAME
表基本信息
字段信息
索引信息
API JSON
通过APIhttps://demo.crudapi.cn/api/metadata/tables/metadata/ca_product
查询ca_product的schema信息, 格式如下：
{
"Name": "ca_product",
"Engine": "InnoDB",
"Version": 10,
"Row_format": "Dynamic",
"Rows": 0,
"Avg_row_length": 0,
"Data_length": 16384,
"Max_data_length": 0,
"Index_length": 32768,
"Data_free": 0,
"Auto_increment": 2,
"Create_time": 1628141282000,
"Update_time": 1628141304000,
"Collation": "utf8mb4_unicode_ci",
"Create_options": "",
"Comment": "产品",
"columns": [{
"Field": "id",
"Type": "bigint unsigned",
"Null": "NO",
"Key": "PRI",
"Extra": "auto_increment",
"Privileges": "select,insert,update,references",
"Comment": "编号"
}, {
"Field": "name",
"Type": "varchar(200)",
"Collation": "utf8mb4_unicode_ci",
"Null": "NO",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "名称"
}, {
"Field": "fullTextBody",
"Type": "text",
"Collation": "utf8mb4_unicode_ci",
"Null": "YES",
"Key": "MUL",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "全文索引"
}, {
"Field": "createdDate",
"Type": "datetime",
"Null": "NO",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "创建时间"
}, {
"Field": "lastModifiedDate",
"Type": "datetime",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "修改时间"
}, {
"Field": "code",
"Type": "varchar(200)",
"Collation": "utf8mb4_unicode_ci",
"Null": "YES",
"Key": "UNI",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "编码"
}, {
"Field": "brand",
"Type": "varchar(200)",
"Collation": "utf8mb4_unicode_ci",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "品牌"
}, {
"Field": "price",
"Type": "decimal(10,0)",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "单价"
}, {
"Field": "weight",
"Type": "decimal(10,0)",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "重量"
}, {
"Field": "length",
"Type": "decimal(10,0)",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "长"
}, {
"Field": "width",
"Type": "decimal(10,0)",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "宽"
}, {
"Field": "high",
"Type": "decimal(10,0)",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "高"
}, {
"Field": "ats",
"Type": "bigint",
"Null": "YES",
"Key": "",
"Extra": "",
"Privileges": "select,insert,update,references",
"Comment": "库存个数"
}],
"indexs": [{
"Table": "ca_product",
"Non_unique": 0,
"Key_name": "PRIMARY",
"Seq_in_index": 1,
"Column_name": "id",
"Collation": "A",
"Cardinality": 0,
"Null": "",
"Index_type": "BTREE",
"Comment": "",
"Index_comment": "",
"Visible": "YES"
}, {
"Table": "ca_product",
"Non_unique": 0,
"Key_name": "UQ_CODE",
"Seq_in_index": 1,
"Column_name": "code",
"Collation": "A",
"Cardinality": 0,
"Null": "YES",
"Index_type": "BTREE",
"Comment": "",
"Index_comment": "",
"Visible": "YES"
}, {
"Table": "ca_product",
"Non_unique": 1,
"Key_name": "ft_fulltext_body",
"Seq_in_index": 1,
"Column_name": "fullTextBody",
"Cardinality": 0,
"Null": "YES",
"Index_type": "FULLTEXT",
"Comment": "",
"Index_comment": "",
"Visible": "YES"
}]
}
核心代码
前端根据API返回的schema信息，转换成crudapi的元数据格式，并显示在UI上, 主要代码在文件metadata/table/new.vue中，通过addRowFromMetadata方法添加字段，addIndexFromMetadata添加联合索引。
addRowFromMetadata(id, t, singleIndexColumns) {
const columns = this.table.columns;
const index = columns.length + 1;
const type = t.Type.toUpperCase();
const name = t.Field;
let length = null;
let precision = null;
let scale = null;
let typeArr = type.split("(");
if (typeArr.length > 1) {
const lengthOrprecisionScale = typeArr[1].split(")")[0];
if (lengthOrprecisionScale.indexOf(",") > 0) {
precision = lengthOrprecisionScale.split(",")[0];
scale = lengthOrprecisionScale.split(",")[1];
} else {
length = lengthOrprecisionScale;
}
}
let indexType = null;
let indexStorage = null;
let indexName = null;
let indexColumn = singleIndexColumns[name];
if (indexColumn) {
if (indexColumn.Key_name === "PRIMARY") {
indexType = "PRIMARY";
} else if (indexColumn.Index_type === "FULLTEXT") {
indexType = "FULLTEXT";
indexName = indexColumn.Key_name;
} else if (indexColumn.Non_unique === 0) {
indexType = "UNIQUE";
indexName = indexColumn.Key_name;
indexStorage = indexColumn.Index_type;
} else {
indexType = "INDEX";
indexName = indexColumn.Key_name;
indexStorage = indexColumn.Index_type;
}
}
const comment = t.Comment ? t.Comment : name;
const newRow = {
id: id,
autoIncrement: (t.Extra === "auto_increment"),
displayOrder: columns.length,
insertable: true,
nullable: (t.Null === "YES"),
queryable: true,
displayable: false,
unsigned: type.indexOf("UNSIGNED") >= 0,
updatable: true,
dataType : typeArr[0].replace("UNSIGNED", "").trim(),
indexType: indexType,
indexStorage: indexStorage,
indexName: indexName,
name: name,
caption: comment,
description: comment,
length: length,
precision: precision,
scale: scale,
systemable: false
};
this.table.columns = [ ...columns.slice(0, index), newRow, ...columns.slice(index) ];
},
addIndexFromMetadata(union) {
let baseId = (new Date()).valueOf();
let newIndexs = [];
const tableColumns = this.table.columns;
console.dir(tableColumns);
for (let key in union) {
const unionLines = union[key];
const newIndexLines = [];
unionLines.forEach((item) => {
const columnName = item.Column_name;
const columnId = tableColumns.find(t => t.name === columnName).id;
newIndexLines.push({
column: {
id: columnId,
name: columnName
}
});
});
const unionLineFirst = unionLines[0];
let indexType = null;
let indexStorage = null;
if (unionLineFirst.Key_name === "PRIMARY") {
indexType = "PRIMARY";
} else if (unionLineFirst.Non_unique === 0) {
indexType = "UNIQUE";
indexStorage = unionLineFirst.Index_type;
} else {
indexType = "INDEX";
indexStorage = unionLineFirst.Index_type;
}
const indexComment = unionLineFirst.Index_comment ? unionLineFirst.Index_comment: unionLineFirst.Key_name;
const newIndex = {
id: baseId++,
isNewRow: true,
caption: indexComment,
description: indexComment,
indexStorage: indexStorage,
indexType: indexType,
name: unionLineFirst.Key_name,
indexLines: newIndexLines
}
newIndexs.push(newIndex);
}
this.table.indexs = newIndexs;
if (this.table.indexs) {
this.indexCount = this.table.indexs.length;
} else {
this.indexCount = 0;
}
}
例子
以ca_product为例子, 点击“加载元数据之后”，表字段和索引都正确地显示了。保存成功之后，已经存在的物理表ca_product会自动被元数据管理起来，后续可以通过crudapi后台继续编辑，通过数据库逆向功能，零代码实现了物理表ca_product的CRUD增删改查功能。
小结
本文主要介绍了数据库逆向功能，在数据库表单已经存在的基础上，通过数据库逆向功能，快速生成元数据，不需要一行代码，我们就可以得到已有数据库的基本crud功能，包括API和UI。类似于phpmyadmin等数据库UI管理系统，但是比数据库UI管理系统更灵活，更友好。目前数据库逆向一次只支持一个表，如果同时存在很多物理表，就需要批量操作了。后续会继续优化，实现批量数据库逆向功能。
附源码地址
GitHub地址
Gitee地址
由于网络原因，GitHub可能速度慢，改成访问Gitee即可，代码同步更新。
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