Assigning variable to a variable inside if statement

I am trying to assign a variable from a prompt input choice with no luck. If the user inputs 1, I want target_db_name = "database2". My code:

while true; do
    read -p  "What is the table name?" table_name
table_name=${table_name,,}
    if hdfs dfs -test -e /foo/$table_name ; 
    then read -p "What is the target database you want to copy the 
“foo.${table_name}” table to?

Your three options are:
1) database1
2) database2
3) database3

Type 1, 2, or 3: " target_db;

(((Here is where I want to state if $target_db = "1" then target_db_name 
= "database1", if $target_db = "2" then target_db_name = "database2" etc...)))

read -p "Would you like to begin the HDFS copy with the following configuration:

Target Database: ${target_db_name}  
Table Name: ${table_name}

Continue (Y/N):"

else echo "Please provide a valid table name.
Exiting this script" ; exit ; fi

done

I have tried creating another if statement with no luck.

"....Type 1, 2, or 3: " target_db;
else if $target_db = "1" then target_db_name = "edw_qa_history"; fi