Tables and flat files have rows and columns of information., , Scalability means a system can grow when demand does., , Data persistence means data might be stored forever., , A relational database links the information in different tables., , A null value means there is no data., , A logical schema outlines the structure of a database., , Physical schema refers to the actual tables, columns and relationships created in the RDBMS., , A row in a table is called a record., , A column in a table is called a field., , A primary key identifies a record uniquely., , Constraints set limitations to prevent problems with a database., , Queries are questions a database can answer., , Non-structured data like pictures and documents don't fit into a database., , Metadata is an example of semi-structured data., , Two types of databases are document and key/value., , Different types of access are manual, direct, programmatic, user interface and utility., , Global or server permissions are usually only for an administrator account., , Permissions can be granted, denied or revoked., , The drop command deletes database objects., , A database dump is a one-time backup of a database that exports the schema, tables, views with the data., .

Understanding Databases (7.1)

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