Android Sqlite:检查表中是否存在行 [英] Android Sqlite: Check if row exists in table
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问题描述
我有一个字符串数组,如果在插入它们之前存在于表中则需要进行检查,以避免重复。什么是SQL查询以及如何将以下值替换为它? :)
I have an array of strings that need to be checked if exists in a table before inserting them in order to avoid duplicates. What is the SQL query and how do I substitute the following values to it? :)
ArrayList<Product> NewProducts= new ArrayList<Product>();
我的产品型号:
public class Product {
public Product()
{
}
public String PID = "pid";
public String getPID() {
return PID;
}
public void setPID(String pID) {
PID = pID;
}
public String getNAME() {
return NAME;
}
public void setNAME(String nAME) {
NAME = nAME;
}
public String PID = "pid";
public String NAME = "name";
}
表名: product_pics
Table name: product_pics
数据库名称: product_db
Database name: product_db
我知道此声明可行:
"SELECT * FROM ' + product_pics + ' WHERE PID=' + pid +'"
如何正确格式化,以便在产品存在时方法返回?
How do I properly format this such that the method returns if the product exists or not?
推荐答案
就像
Cursor cursor = null;
String sql ="SELECT PID FROM "+TableName+" WHERE PID="+pidValue;
cursor= db.rawQuery(sql,null);
Log("Cursor Count : " + cursor.getCount());
if(cursor.getCount()>0){
//PID Found
}else{
//PID Not Found
}
cursor.close();
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