henryliangt
commented
1 year ago Open henryliangt opened 1 year ago
henryliangt
commented
1 year ago henryliangt
commented
1 year ago show dbs use city_data db.createCollection("climate_original")
mongoimport --jsonArray --db twitter --collection tweets --file tweets.json mongoimport --jsonArray --db city_data --collection climate_original --file climate.json
climate_original
Relational Database Glossary Attribute Data that describes an entity; the formal term for a column in a relation.
Concurrency control Mechanisms to ensure that a database remains consistent and accurate when multiple users are using the same database.
Data Model An abstract model that organises elements of data and standardizes how they relate to one another and to the properties of real-world entities. (Data Model Wiki Entry (Links to an external site.)) Database Partitioning A process to divide a large table into many smaller parts. Vertical partitioning stores a table as two or more tables that are projections of the original table. Horizontal partitioning splits the rows of a table between multiple tables with the same structure.
Index A data structure in a database that provides a logical ordering of data based on key values.
Foreign key (FK) An attribute (or combination of attributes) in a table that refers to the primary key in another table. The table with the foreign key is called the child table, and the table with the primary key is called the referenced or parent table. The referential integrity constraint is related with the foreign key concept. It states that every non-null foreign key value must match an existing primary key value.
Immutable Unable to be changed. Wherever possible, primary keys should be immutable as long the row containing the key is in the database.
Join A relational algebra operation that combines two relations horizontally by matching values between the two tables. Most valid joins involve matching primary key values to foreign key values.
Null A database value, distinct from a blank or zero, meaning “unknown.”
Primary key (PK) A column or combination of columns whose value uniquely identifies each row in a relation. The entity integrity constraint is related with primary key concept. It states that the table should have a unique and non-null primary key.
Relational Model A widely used data model that describes the world as a collection of inter-related relations (or tables).
SQL Structured Query Language, a standard language for accessing and manipulating relational databases.
Table A term used synonymously with relation in the relational data model.
Tuple The formal term for a row in a relation.
Write-ahead logging (WAL) A family of techniques for providing atomicity and durability in database systems. A write ahead log is an append-only auxiliary disk-resident structure used for crash and transaction recovery. The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database. [WAL wiki entry (Links to an external site.)]
Many Definitions are based on the Glossary section of Jan Harrington, Relational Database Design and Implementation 4th Edition unless specified otherwise.