SQL ADDA

  Table of Contents What is a Data Model? What is Data Modeling? Data Modeling Examples Types of Data Modeling Data Modelling Techniques Data Modeling Tools Importance of Data Modeling Learn Data Modeling Data  is changing the way the world functions. It can be a study about disease cures, a company’s revenue strategy, efficient building construction, or those targeted ads on your social media page; it is all due to data.  This data refers to information that is machine-readable as opposed to human-readable. For example, customer data is meaningless to a product team if they do not point to specific product purchases. Similarly, a marketing team will have no use of that same data if the IDs didn’t relate to specific price points during buying. This is where Data Modeling comes in. It is the process that assigns relational rules to data. A Data Model un-complicates data into useful information that organizations can then use for decision-making and strategy.  Accordin...

  Data File Architecture Data File architecture has the following components − File Groups Database files can be grouped together in file groups for allocation and administration purposes. No file can be a member of more than one file group. Log files are never part of a file group. Log space is managed separately from data space. There are two types of file groups in SQL Server, Primary and User-defined. Primary file group contains the primary data file and any other files not specifically assigned to another file group. All pages for the system tables are allocated in the primary file group. User-defined file groups are any file groups specified using the file group keyword in create database or alter database statement. One file group in each database operates as the default file group. When SQL Server allocates a page to a table or index for which no file group was specified when they were created, the pages are allocated from default file group. To switch the default file grou...

  We have classified the architecture of SQL Server into the following parts for easy understanding − General architecture Memory architecture Data file architecture Log file architecture General Architecture Client  − Where the request initiated. Query  − SQL query which is high level language. Logical Units  − Keywords, expressions and operators, etc. N/W Packets  − Network related code. Protocols  − In SQL Server we have 4 protocols. Shared memory (for local connections and troubleshooting purpose). Named pipes (for connections which are in LAN connectivity). TCP/IP (for connections which are in WAN connectivity). VIA-Virtual Interface Adapter (requires special hardware to set up by vendor and also deprecated from SQL 2012 version). Server  − Where SQL Services got installed and databases reside. Relational Engine  − This is where real execution will be done. It contains Query parser, Query optimizer and Query executor. Query Parser (Command Pa...

  DECLARE TotalUpd NUMBER( 36 ) : = 0 ; BEGIN dbms_output.put_line ( 'Job Start time............... : ' || TO_CHAR(SYSDATE, ' hh24:mi:ss' )); UPDATE Asset SET _status = 'PROGRESS' WHERE status IS null ; TotalUpd : = SQL % ROWCOUNT; IF TotalUpd = 0 THEN dbms_output.put_line ( 'No more data to update.' ); ELSE dbms_output.put_line( 'Total Records Updated. : ' || TotalUpd); END IF; COMMIT ; EXCEPTION WHEN OTHERS THEN dbms_output.put_line ( 'Error while status as SUCCESS ' ); END ; Declare  @val1  int ;   Declare  @val2  int ;   BEGIN  TRY   Set  @val1=8;   Set  @val2=@val1/0; /* Error Occur Here */   END  TRY   BEGIN  CATCH   Print  'Error Occur that is:'    Print Error_Message()   END  ...