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JAVASCRIPTHTMLCSSPYTHONSQLJAVACPPCSHARPPHPTYPESCRIPTCRUBYGOSWIFTKOTLINRUSTRBASHSCALAOBJECTIVE-CDARTPERLLUAMATLABXMLJSONMARKDOWNASSEMBLYLATEXYAMLSOLIDITYBLOCKCHAIN

Topics

Introduction to SQL

What is SQL?SQL HistorySQL StandardsSQL vs NoSQLSQL Database Management Systems

SQL Basics

SQL SyntaxSQL CommentsSQL Data TypesSQL OperatorsSQL ExpressionsSQL LiteralsSQL IdentifiersSQL KeywordsSQL Case Sensitivity

SQL Database Fundamentals

Database ConceptsTables and FieldsPrimary KeysForeign KeysIndexesConstraintsNormalizationDenormalizationSQL Schema Design

SQL Data Manipulation

SQL SELECT StatementSQL INSERT StatementSQL UPDATE StatementSQL DELETE StatementSQL MERGE StatementSQL AliasesSQL WildcardsSQL LIKE OperatorSQL IN OperatorSQL BETWEEN OperatorSQL NULL ValuesSQL ORDER BY ClauseSQL LIMIT ClauseSQL OFFSET Clause

SQL Filtering and Sorting

SQL WHERE ClauseSQL AND, OR, NOT OperatorsSQL GROUP BY ClauseSQL HAVING ClauseSQL DISTINCT KeywordSQL TOP Clause

SQL Joins

SQL INNER JOINSQL LEFT JOINSQL RIGHT JOINSQL FULL OUTER JOINSQL CROSS JOINSQL Self JOINSQL Natural JOINSQL Multiple JOINs

SQL Functions

SQL Aggregate FunctionsSQL Scalar FunctionsSQL String FunctionsSQL Numeric FunctionsSQL Date FunctionsSQL Conversion FunctionsSQL System FunctionsSQL User-Defined Functions

SQL Subqueries

SQL Subquery BasicsCorrelated SubqueriesNested SubqueriesSQL EXISTS OperatorSQL ANY and ALL OperatorsSubqueries in SELECTSubqueries in FROMSubqueries in WHERE

SQL Views

Creating SQL ViewsAltering SQL ViewsDropping SQL ViewsUpdatable ViewsMaterialized ViewsView Limitations

SQL Transactions

SQL Transaction BasicsACID PropertiesBEGIN TRANSACTIONCOMMITROLLBACKSAVEPOINTTransaction Isolation Levels

SQL Data Definition

SQL CREATE TABLESQL ALTER TABLESQL DROP TABLESQL TRUNCATE TABLESQL CREATE INDEXSQL DROP INDEXSQL CREATE DATABASESQL ALTER DATABASESQL DROP DATABASE

SQL Data Control

SQL GRANTSQL REVOKESQL RolesSQL UsersSQL Privileges

SQL Performance Optimization

SQL Query OptimizationSQL Execution PlansSQL Index OptimizationSQL Query TuningSQL CachingSQL Partitioning

Advanced SQL Concepts

SQL Stored ProceduresSQL TriggersSQL CursorsSQL Common Table ExpressionsSQL Window FunctionsSQL Pivot and UnpivotSQL JSON OperationsSQL XML OperationsSQL Full-Text Search

SQL Best Practices

SQL Naming ConventionsSQL Code OrganizationSQL Error HandlingSQL Security Best PracticesSQL Backup and RecoverySQL Version Control

SQL Backup and Recovery

SQL backup and recovery are crucial processes in database management that safeguard data integrity and ensure business continuity. These techniques protect against data loss due to hardware failures, software errors, or human mistakes.

Database Backup

Backup is the process of creating copies of database files to preserve data. There are three main types of backups:

  • Full backup: Copies the entire database
  • Differential backup: Copies only the data changed since the last full backup
  • Transaction log backup: Copies the transaction log, which records all database modifications

Backup Example

-- Full backup
BACKUP DATABASE YourDatabase
TO DISK = 'C:\Backups\YourDatabase.bak'
WITH FORMAT, INIT, NAME = 'Full Backup of YourDatabase';

-- Transaction log backup
BACKUP LOG YourDatabase
TO DISK = 'C:\Backups\YourDatabase_Log.trn'
WITH NAME = 'Transaction Log Backup of YourDatabase';

Database Recovery

Recovery is the process of restoring a database to a consistent state after a failure. It involves applying backed-up data and transaction logs to reconstruct the database.

Recovery Example

-- Restore full backup
RESTORE DATABASE YourDatabase
FROM DISK = 'C:\Backups\YourDatabase.bak'
WITH RECOVERY;

-- Restore transaction log
RESTORE LOG YourDatabase
FROM DISK = 'C:\Backups\YourDatabase_Log.trn'
WITH RECOVERY;

Best Practices

  • Regularly schedule backups based on data criticality and change frequency
  • Store backups in multiple secure locations, including off-site
  • Test recovery procedures periodically to ensure effectiveness
  • Implement a transaction logging strategy for point-in-time recovery
  • Use database management systems with built-in backup and recovery tools

Recovery Models

SQL Server offers three recovery models that affect backup and recovery strategies:

  1. Simple: No log backups, limited to full and differential backups
  2. Full: Supports all backup types and point-in-time recovery
  3. Bulk-logged: Similar to full, but with minimal logging for bulk operations

Considerations

When implementing backup and recovery strategies, consider the following:

  • Recovery Time Objective (RTO): Maximum acceptable downtime
  • Recovery Point Objective (RPO): Maximum acceptable data loss
  • Storage requirements for backups
  • Network bandwidth for backup and restore operations
  • Regulatory compliance and data retention policies

Automated Backup Solutions

Many database management systems offer automated backup solutions. These tools can schedule backups, manage retention policies, and even perform integrity checks on backup files.

-- Create a maintenance plan for automated backups
USE msdb;
GO

EXEC sp_add_maintenance_plan 'Daily Full Backup';
GO

EXEC sp_add_maintenance_plan_db 'Daily Full Backup', 'YourDatabase';
GO

EXEC sp_add_maintenance_plan_job 'Daily Full Backup', 'Daily Full Backup Job';
GO

By implementing robust backup and recovery strategies, database administrators can ensure data integrity and minimize the impact of potential failures on business operations.

Related Concepts