ACCTG 1 Lecture Notes - Lecture 3: Java Database Connectivity, Jdbc Driver
Document Summary
Input: sql query is issued by the user. Step 1: parser creates a na ve (canonical) tree t of query. Step 2: optimizer applies inferential rules to transform tree t to an equivalent and efficient tree. T* i. e. , t* produces exactly the same results as t after re-arranging algebra operators. Step 3: generate code for optimal tree t* within 2-2. 5 ms. Step 4: execute the operators with the order dictated in t* Step 5: return/show the results to the user. Inject projections after selections and before joins thus retrieving only the attributes we need! Jdbc: simply, a way to call sql commands from a java program. It is made up from java function libraries and calls, objects, and classes, implemented for a dbs, a. k. a. Jdbc driver: a java program can have many connections to several different databases, thus, connecting to different jdbc drivers (running on different machines) Model: client-server paradigm: client is the application program, server is the db server/machine.
