Retrieving Data from Single Table

Simplified Syntax of SELECT Statement SELECT select_list [FROM table_source] [WHERE search_condition] [ORDER BY order_by_list] 4 Clauses of SELECT Clause Description SELECT Describes col included in result set FROM Names table query retrieves data from WHERE Conditions must be met for row to be included in result set *optional* ORDER BY How rows in result set…

SQL Statements

Statements: Divided into 2 categories DML Data Manipulation Language: Statements work w/data in DB 4 Statements that app programmers use most DDL Data Definition Language: Statements work w/objects in DB Large Sys: DBA: Maintain existing DB’s for faster perf/create new DB’s Data DML SQL Statements Statement Description SELECT Retrieve data from 1/more tables INSERT Adds…

Intelligent Storage

Intelligent storage systems: Feature-rich RAID arrays: Provide highly optimized I/O processing Config w/large amt of mem Multiple I/O paths Algs to meet reqs of per-sensitive apps Support for newer tech like: Lash drives Virtual storage provisioning Automated storage tiering New dimension to storage sys perf/scalability/avail Components (storage processor/controller): Front end: I/O reqs received from host…

Data Protection: RAID

1980’s: Business growth: New apps/DBs/storage capacity demand SLED: Single Large Expensive Drive: Data stored on SLED during this time Couldn’t meet required perf lvls b/c of limited I/Os. Today: Disk drives: Susceptible to failures: Mechanical wear/env factors: Data loss Greater # of drives in storage array? Greater probability of disk failure in array RAID: Leverages…

DB/SQL Ch. 1&2

Field Single char/attribute of person/place/obj/event/idea Table Collection of fields: Person/place/obj/event/idea Field value Specific content of field Database AKA: Relational database: Collection of related tables Common field Connects records in separate tables Primary key: Field/collection of fields: Values ID each record in table No 2 records contain same value for primary key field Foreign key: Forming…

Intro to Info Storage: Ch. 1

Storage: Repository: Usr stores/retrieves | Data: Article collection that can be drawn from [Bills, etc.] Contribution to digital data growth: Better data-processing Lower cost Faster comm tech Growth: Apps/smart devices Types of Data: Structured/Unstructured: Based on how stored/managed Structured Rows/columns Rigid fmt Process/retrieve quickly Typically uses DBMS [db mgmt sys] Unstructured Elements: No rows/columns Difficult…