如何使用JAVA在Oracle中编写“ INSERT IF EXISTS UPDATE”

Question

I have a ERROR_MSG table which stores error messages with some ids. I want to insert error message if id is not present in table and if its present update error message. Inserting using below java JDBC code.

ID ERROR_MSG
1  ERR1
2  ERR2
3  ERR3

This is my code:

insertQry = "SQL";
Connection con = null;
PreparedStatement stmt = null;
try {
    con = getDataSource().getConnection();
    stmt = con.prepareStatement(insertQry);
    for(ListingAckNackData errorList: listOfListingERROR) {
        stmt.setLong(1, eqGlobalData.getSrcMsgId());
        stmt.setString(2, errorList.getGliId());
        if (null != errorList.getListingRevisionNo()) {
            stmt.setInt(3, errorList.getListingRevisionNo());
        } else {
            stmt.setNull(3, Types.NULL);
        }
        if (null != errorList.getErrorMessage()) {
            stmt.setString(4, errorList.getErrorMessage());
        } else {
            stmt.setNull(4, Types.NULL);
        }
        stmt.addBatch();
    }
    stmt.executeBatch();
}

Answer 1

The simplest solution in JAVA is to check if the row exist.

You start by getting a row count for the specific id you want to insert/update

select count('a') as rowExist from table where id = ?

Then, based on the result, you can easily create your query

if(rowExist > 0){
    query = "update ..";
else
    query = "insert ...";

Note that the parameters are probably not in the same order as you expect, you need to create the insert in the correct order to have the id at the end (since update need a where clause)

insert into Table (name, birthday, id) values (?, ?, ?)
update Table set name = ?, birthday = ? where id = ?

Answer 2

It is possible to run a database statement as questioned. Simply use SQL command MERGE INTO... IF NOT MATCHED INSERT... IF MATCHED UPDATE ... You will find an full example and documentation here .