Char(n)
CHAR(n) is a fixed-length SQL character-string data type whose values occupy the declared character length, typically with trailing-space padding.
Learn Rust in a Month of Lunches
Rust's char type represents one Unicode scalar value and occupies four bytes.
- How it is used
- Uses `char` to represent one Unicode scalar value and to distinguish characters from string byte lengths.
- How deep it goes
- Defines `char`, works through storage and conversion examples, then surveys selected methods without cataloging them all.
- Examples
- Shows quoted characters, byte-size comparisons, a failed integer cast, Unicode escapes, and conversions from integers.
- What you can do after
- Evaluate/understand it by distinguishing fixed-size `char` storage from UTF-8 byte lengths and choosing character counts when needed.
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Grokking Relational Database Design
CHAR is a fixed-length SQL character-string data type whose declared length determines its stored character width.
- How it is used
- Guides choosing a string type for attributes whose values have a uniform length.
- How deep it goes
- Defines selection rules and applies declared widths to card, expiry-date, and product-code attributes.
- Examples
- Uses state or province codes, card numbers, expiry dates, and UPC product codes.
- What you can do after
- Apply it to define fixed-width codes and numeric-looking identifiers as strings rather than integers.
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Modern C, Third Edition
char is a C character type that occupies exactly one byte and is intended to represent individual characters.
- How it is used
- Represents printable characters and string data while also serving as a narrow integer type.
- How deep it goes
- Defines size, signedness variation, object representation, and arithmetic promotion, but does not develop advanced pointer techniques.
- Examples
- Uses printable character data, sizeof(char), arithmetic promotion, and an unsigned-char view of an object.
- What you can do after
- Evaluate/understand char declarations, byte size, promotion behavior, and the distinction between character data and object representation.
100 SQL Server Mistakes and How to Avoid Them
CHAR is a SQL Server fixed-length, non-Unicode character data type that stores one byte per character and pads values to the declared length.
- How it is used
- Contrasts fixed-length and variable-length strings when choosing SQL Server column types.
- How deep it goes
- Traces whitespace padding into byte usage, 8 KB pages, and row-slot metadata.
- Examples
- Uses US address fields, CHAR(8) containing Hello!, and a DepartmentCode alteration.
- What you can do after
- Evaluate fixed-length string choices by accounting for padding and declared storage length.
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Modern C
char is the C integer type used to represent characters and small integer values.
- How it is used
- Represents basic-set characters and supports string and character-array operations.
- How deep it goes
- Explains representation, termination, initialization, encoding assumptions, and library interfaces, but defers broader integer details.
- Examples
- Uses jay initializers and a complete program copying argv[0] into a variable-length char array.
- What you can do after
- Apply it via string.h by distinguishing terminated strings from length-bounded char arrays.
Related concepts
- From traituses · From is Rust’s standard-library trait for infallibly converting a value of one type into another type.
- varchar data typealternative to · VARCHAR is a variable-length character-string data type whose values may be subject to a declared maximum length.
- TryFromuses · TryFrom is a Rust standard-library trait for fallible conversion between types, returning a result that indicates success or failure.
- fixed-length stringkind of · A fixed-length string is a character data type whose storage allocation is determined by its declared length and may include padding.
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