1. First install PLSQL Developer as usual. What I installed here is 64-bit, and the installation directory is: D:\Program Files\PLSQL Developer
2. Run "plsqldev.exe", run PLSQL Developer, the pop-up box is as follows:
After a little look, you will find that there are two things missing, the first: the Connect as option is missing, and the second: there is nothing in the select box behind the Database (at this time, I will be worried: I can set it there to connect to my own database? , you can't connect to the desired database if you fill it blindly).
I checked online and said that PLSQL Developer does not support Oracle64-bit, and you need to install a client before you can use it. (PS: I personally feel that this statement is a bit far-fetched - if you want to connect to the SQL Server database, you need to install a server or you need to get a client or you can't connect - it may be the reason why it is not supported. On the premise of the client, I use Navicat for Oracle to connect to the remote Oracle server. This may be because the connection method of PLSQL Developer is different from Navicat for Oracle, it just needs to rely on the client)
3. Install the Oracle client. I installed Instant Client Setup.exe, 11g, 32-bit, and the directory is: D:\Program Files (x86)\Oracle\Instant Client. After the installation is complete, it will pop up a file for editing, close it directly without editing, and talk about this file later.
4. Run "plsqldev.exe" again, run PLSQL Developer, the pop-up box is as follows: 
After reading, you will find that the two boxes in the second step have come out, it looks normal, enter the correct user name, password, Database Select DummayDatabase, Connect as, select Normal, click "OK", and a pop-up box will remind you that "No listeners". Obviously, the database was chosen incorrectly. What is this DummayDatabase? Where is it set? That's right, it is set in the file that pops up in the last step of installing the client, and the file name is tnsnames.ora.
4. Find tnsnames.ora (my local is called Oracle Database Instant Client) from the program directory of the client in the start menu, or open the installation directory of the client \..\..\network\admin or directly search for tnsnames.ora, ( My local directory is D:\Program Files (x86)\Oracle\Instant Client\network\admin), open tnsnames.ora, the basic structure and the places that need to be modified are shown in the figure: 
The DummayDatabase seen in the Database in the previous step is the figure The value marked in 1 place, this value can not be changed, but it is recommended to change it to a familiar name, 2 places fill in the ip address of the oracle server you want to connect to (I am the local connection here), and 3 places are the port number. This is not required. More to say, 4 is the name of the oracle server instance (I am orcl10g here). If there are multiple instances, you can copy this structure down, modify the name of DummayDatabase, and save it at last.
5. Repeat the steps of 4 and find that the oracle can be correctly connected.
The installation software is too large to upload to the attachment, so I got Baidu cloud disk. The connection address: http://pan.baidu.com/s/1kVHilvD
At this point, use the PLSQL Developer tool to connect to oracle to complete.