Sql中Insert添加语句如何不重复

迈不过友情╰ 2022-09-24 12:22 287阅读 0赞

在Insert中添加一个查询语句query，如果该列表中有查询值则返回false  
**代码如下：**

//insert data
        public boolean insertData(MyData data){
            String str = "";
            long resCode = -1L;
            // 创建ContentValues对象
            ContentValues values = new ContentValues();
            // 向该对象中插入键值对，其中键是列名，值是希望插入到这一列的值，值必须和数据库当中的数据类型一致
    
            //查询语句查该值
            Cursor cursor = sqliteDatabase.query("user", new String[]{
       "id"}, "id = ?", new String[]{data.getId()}, null, null, null);
            if(cursor!=null){
                while(cursor.moveToNext()){
                    str = cursor.getString(0);
                }
            }
    
            //判断是否存在
            if(str.equals(data.getId())){
                Toast.makeText(context, "添加失败", Toast.LENGTH_LONG).show();
            }else{
                values.put("id", data.getId());
                values.put("name", data.getAddress());
                resCode = sqliteDatabase.insert("user", null, values);
            }
            if(resCode == -1) return false;
            return true;
    
        }

**activity部分代码：**

case R.id.myButton_3:
        // 获取值
        text1 = myedittext1.getText().toString();
        text2 = myedittext2.getText().toString();
    
        MyData data = new MyData();
        data.setId(text1);
        data.setAddress(text2);
    
        boolean res = myUtils.insertData(data);
        if(res == true){
            Toast.makeText(SQLiteActivity.this,"添加成功", Toast.LENGTH_LONG).show();
        }else{
            Toast.makeText(SQLiteActivity.this,"添加失败", Toast.LENGTH_LONG).show();
            }
        break;

class MyData：

package com.example.sqlite;
    
    import java.io.Serializable;
    
    public class MyData implements Serializable{
        
        private String id = "";
        private String address = "";
        public String getId() {
            return id;
        }
        public void setId(String id) {
            this.id = id;
        }
        public String getAddress() {
            return address;
        }
        public void setAddress(String address) {
            this.address = address;
        }
    
    }