Identifiers are case sensitive

Yes, Python is a case-sensitive language, i.e., it treats uppercase and lowercase characters differently. This applies to identifiers too. You must avoid using the same name with different cases while naming identifiers. It is always good to use names that are more easily understood. If you want to store counts of 2 values, you would rather name your variables count1 and count2 instead of naming them C and c. Although the latter would give you separate variables, it can cause a lack of understanding in the longer run. Rules for Identifiers in Python To construct a Python identifier, a few requirements must be fulfilled. • Reserved keywords (special words used for a specific purpose, e.g., while, for, if, etc.) cannot be used as identifier names. • Python identifiers can contain lowercase letters ( a-z), uppercase letters ( A-Z), numerals ( 0-9), and underscores ( _ ). This means that Identifiers in Python cannot contain special characters except underscore in them. • The name of the identifier cannot begin with a number. • The name of a Python identifier can begin with an underscore. • The length of the identifier name is unrestricted. • The names of Python identifiers are case sensitive. Example of Python Identifiers Based on the rules mentioned above, identifiers in Python can be created. To understand this better, let's consider a few examples as shown below: • Valid Identifiers • count1 : contains only letters and numbers • count_oddNo : contains all valid characters •...

In this article In SQL statements and catalog function arguments, identifiers and quoted identifiers can be either case-sensitive or not, which an application can determine by calling SQLGetInfo with the SQL_IDENTIFIER_CASE and SQL_QUOTED_IDENTIFIER_CASE options. Each of these options has four possible return values: one stating that the identifier or quoted identifier case is sensitive and three stating that it is not sensitive. The three values that are not case-sensitive further describe the case in which identifiers are stored in the system catalog. How identifiers are stored in the system catalog is relevant only for display purposes, such as when an application displays the results of a catalog function; it does not change the case-sensitivity of identifiers.

Abstract: Exploring database delimited identifiers and case sensitivity: the effect of quoting table and field names in the various DBMS. Almost every month I get a bug report for identifiers (table and field names) not being quoted as expected. Or, when they are quoted, the query fails for unknown reasons. Most of the times, the problem is not within MDB2: there's simply a lot of confusion on how quoting the identifiers affects the table/field creation and the subsequent queries that reference them. I think it's time to dispell some myths and shed some light on the topic of identifier quoting and case sensitivity. The SQL:2008 and SQL-99 and standards The SQL:2008 and SQL-99 standards define databases to be case insensitive for identifiers unless they are quoted. Lower case characters may be used in identifiers and keywords, but are considered to be their upper case counterparts. In other words, delimited identifiers are case sensitive ("table_name" != "Table_Name"), while non quoted identifiers are not, and are transformed to upper case (table_name => TABLE_NAME). The SQL-92 standard is even more explicit on how to handle lower/upper case letters in identifiers, while I find it a bit less clear on how delimited identifiers should be treated. Now, as everyone knows, not all the DBMS vendors adhere to the SQL standards in a strict way. Let's see how each one of them interprets it on this issue. • First, I'm going to create a table without quoting the name, and then to crea...

Any character data to be processed by PL/SQL or stored in a database must be represented as a sequence of bytes. The byte representation of a single character is called a character code. A set of character codes is called a character set. Every Oracle database supports a database character set and a national character set. PL/SQL also supports these character sets. This document explains how PL/SQL uses the database character set and national character set. PL/SQL uses the database character set to represent: • Stored source text of PL/SQL units For information about PL/SQL units, see " • Character values of data types CHAR, VARCHAR2, CLOB, and LONG For information about these data types, see " The database character set can be either single-byte, mapping each supported character to one particular byte, or multibyte-varying-width, mapping each supported character to a sequence of one, two, three, or four bytes. The maximum number of bytes in a character code depends on the particular character set. Every database character set includes these basic characters: • Latin letters: A through Z and a through z • Decimal digits: 0 through 9 • Punctuation characters in • Whitespace characters: space, tab, new line, and carriage return PL/SQL source text that uses only the basic characters can be stored and compiled in any database. PL/SQL source text that uses nonbasic characters can be stored and compiled only in databases whose database character sets support those nonbasic chara...

In a provisioning profile I set my app id to com.mycompany.lowercaseappname, but in Xcode 4 the bundle identifier is auto configured to use my $, which is capitalized (I want the user to see it capitalized under the app icon). Is this ok or do I need to change the bundle id manually in Xcode to lower case? The bundle identifier must be globally unique (not match any other application in the world) but it doesn't have to match the application name, nor is the case important. However, remember that the preferences file will be named the same as the identifier so the identifier should be recognizable to the user as belonging to your application. You can override the auto-configured bundle identifier in Xcode4 by pressing Command-1 to see the navigator view, clicking on the xxx-Info.plist file (where xxx is your application name) and changing the Bundle Identifier string to anything you want. It doesn't have to contain the $ variable. Thanks for contributing an answer to Stack Overflow! • Please be sure to answer the question. Provide details and share your research! But avoid … • Asking for help, clarification, or responding to other answers. • Making statements based on opinion; back them up with references or personal experience. To learn more, see our

An identifier is an arbitrarily long sequence of digits, underscores, lowercase and uppercase Latin letters, and most Unicode characters. The first character of a valid identifier must be one of the following: • uppercase latin letters A-Z • lowercase latin letters a-z • underscore • any Unicode character with the Unicode property Any other character of a valid identifier must be one of the following: • digits 0-9 • uppercase latin letters A-Z • lowercase latin letters a-z • underscore • any Unicode character with the Unicode property The lists of characters with properties XID_Start and XID_Continue can be found in Identifiers are case-sensitive (lowercase and uppercase letters are distinct), and every character is significant. Every identifier must conform to Note: Support of Unicode identifiers is limited in most implementations, e.g. Contents • 1 In declarations • 1.1 Zombie identifiers • 2 In expressions • 2.1 Unqualified identifiers • 2.2 Qualified identifiers • 3 Names • 4 Defect reports • 5 See also [ In declarations An identifier can be used parameter packs (since C++11) goto labels, and other entities, with the following exceptions: • the identifiers that are • The only place they can be used as non-keywords is in an attribute-token (e.g. [ [ private ] ] is a valid (since C++11) • the identifiers that are • the identifiers with special meaning ( final , import, module (since C++20) and override) are used explicitly in a certain context rather than being regular i...

Is there a reason why Oracle is case sensitive and others like SQL Server, and MySQL are not by default? I know that there are ways to enable/disable case sensitivity, but it just seems weird that oracle differs from other databases. I'm also trying to understand reasons for case sensitivity. I can see where "Table" and "TaBlE" can be considered equivalent and not equivalent, but is there an example where case sensitivity would actually make a difference? I'm somewhat new to databases and am currently taking a class. By default, Oracle identifiers (table names, column names, etc.) are case- insensitive. You can make them case-sensitive by using quotes around them (eg: SELECT * FROM "My_Table" WHERE "my_field" = 1). SQL keywords ( SELECT, WHERE, JOIN, etc.) are always case-insensitive. On the other hand, string comparisons are case- sensitive (eg: WHERE field='STRING' will only match columns where it's 'STRING') by default. You can make them case-insensitive by setting NLS_COMP and NLS_SORT to the appropriate values (eg: LINGUISTIC and BINARY_CI, respectively). Note: When inquiring data dictionary views (eg: dba_tables) the names will be in upper-case if you created them without quotes, and the string comparison rules as explained in the second paragraph will apply here. Some databases (Oracle, IBM DB2, PostgreSQL, etc.) will perform case-sensitive string comparisons by default, others case-insensitive (SQL Server, MySQL, SQLite). This isn't standard by any means, so just b...

An identifier is an arbitrarily long sequence of digits, underscores, lowercase and uppercase Latin letters, and most Unicode characters. The first character of a valid identifier must be one of the following: • uppercase latin letters A-Z • lowercase latin letters a-z • underscore • any Unicode character with the Unicode property Any other character of a valid identifier must be one of the following: • digits 0-9 • uppercase latin letters A-Z • lowercase latin letters a-z • underscore • any Unicode character with the Unicode property The lists of characters with properties XID_Start and XID_Continue can be found in Identifiers are case-sensitive (lowercase and uppercase letters are distinct), and every character is significant. Every identifier must conform to Note: Support of Unicode identifiers is limited in most implementations, e.g. Contents • 1 In declarations • 1.1 Zombie identifiers • 2 In expressions • 2.1 Unqualified identifiers • 2.2 Qualified identifiers • 3 Names • 4 Defect reports • 5 See also [ In declarations An identifier can be used parameter packs (since C++11) goto labels, and other entities, with the following exceptions: • the identifiers that are • The only place they can be used as non-keywords is in an attribute-token (e.g. [ [ private ] ] is a valid (since C++11) • the identifiers that are • the identifiers with special meaning ( final , import, module (since C++20) and override) are used explicitly in a certain context rather than being regular i...

Abstract: Exploring database delimited identifiers and case sensitivity: the effect of quoting table and field names in the various DBMS. Almost every month I get a bug report for identifiers (table and field names) not being quoted as expected. Or, when they are quoted, the query fails for unknown reasons. Most of the times, the problem is not within MDB2: there's simply a lot of confusion on how quoting the identifiers affects the table/field creation and the subsequent queries that reference them. I think it's time to dispell some myths and shed some light on the topic of identifier quoting and case sensitivity. The SQL:2008 and SQL-99 and standards The SQL:2008 and SQL-99 standards define databases to be case insensitive for identifiers unless they are quoted. Lower case characters may be used in identifiers and keywords, but are considered to be their upper case counterparts. In other words, delimited identifiers are case sensitive ("table_name" != "Table_Name"), while non quoted identifiers are not, and are transformed to upper case (table_name => TABLE_NAME). The SQL-92 standard is even more explicit on how to handle lower/upper case letters in identifiers, while I find it a bit less clear on how delimited identifiers should be treated. Now, as everyone knows, not all the DBMS vendors adhere to the SQL standards in a strict way. Let's see how each one of them interprets it on this issue. • First, I'm going to create a table without quoting the name, and then to crea...

Is there a reason why Oracle is case sensitive and others like SQL Server, and MySQL are not by default? I know that there are ways to enable/disable case sensitivity, but it just seems weird that oracle differs from other databases. I'm also trying to understand reasons for case sensitivity. I can see where "Table" and "TaBlE" can be considered equivalent and not equivalent, but is there an example where case sensitivity would actually make a difference? I'm somewhat new to databases and am currently taking a class. By default, Oracle identifiers (table names, column names, etc.) are case- insensitive. You can make them case-sensitive by using quotes around them (eg: SELECT * FROM "My_Table" WHERE "my_field" = 1). SQL keywords ( SELECT, WHERE, JOIN, etc.) are always case-insensitive. On the other hand, string comparisons are case- sensitive (eg: WHERE field='STRING' will only match columns where it's 'STRING') by default. You can make them case-insensitive by setting NLS_COMP and NLS_SORT to the appropriate values (eg: LINGUISTIC and BINARY_CI, respectively). Note: When inquiring data dictionary views (eg: dba_tables) the names will be in upper-case if you created them without quotes, and the string comparison rules as explained in the second paragraph will apply here. Some databases (Oracle, IBM DB2, PostgreSQL, etc.) will perform case-sensitive string comparisons by default, others case-insensitive (SQL Server, MySQL, SQLite). This isn't standard by any means, so just b...