Overview You are going to build the first component of a simple database engine in Java. The required functionalities are creating tables, building indices, storing data, deleting data, and querying. Follow the below description Tables
- Each table/relation will be stored as pages on disk (each page is a separate file).
- A page has a predetermined fixed maximum number of rows (N). For example, if a table has 40000 tuples, and if N=200, the table will be stored in 200 files.
- You are required to use Java’s binary object file (.class) for emulating a page (to avoid having you work with file system pages, which is not the scope of this course). A single page must be stored as a serialized Vector (java.util.Vector) , because Vectors are thread safe). Note that you can save/load any Java object to/from disk by implementing the java.io.Serializable interface. You don’t actually need to add any code to your class to save it the hard disk.
- A single tuple should be stored in a separate object inside the binary file.
- If all the rows in a page are deleted, then you are required to delete that page. Do not keep around completely empty pages. In the case of insert, if you are trying to insert in a full page, shift one row down to the following page. Do not create a new page unless you are in the last page of the table and that last one was full.
- Each user table has meta data associated with it; number of columns, data type of columns, which columns have indices built on them.
- You will need to store the meta-data in a text file. This should have the following layout: TableName,ColumnName, ColumnType, ClusteringKey, IndexName, IndexType, min, max
- ClusteringKey is set true if the column is the primary key. you will always sort the rows in the table according to the primary key.
- min and max refer to the minimum and maximum values possible for that column.
- You are required to use an Octree to support creating indices