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https://github.com/marcobambini/sqlite-createtable-parser

A parser for SQLite create table sql statements.
https://github.com/marcobambini/sqlite-createtable-parser

c parse parser sqlite sqlite3

Last synced: 12 days ago
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A parser for SQLite create table sql statements.

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README 

        
## SQLite CREATE and ALTER TABLE Parser

A parser for SQLite [create table](https://www.sqlite.org/lang_createtable.html) and [alter table](https://www.sqlite.org/lang_altertable.html) sql statements.



* Extremely fast parser with no memory copy overhead

* MIT licensed with no dependencies (just drop the C file into your project)

* Never recurses or allocates more memory than it needs

* Very simple API 



## Motivation

[SQLite](https://www.sqlite.org/) is a very powerful software but it lacks an easy way to extract complete information about tables and columns constraints. This drawback in addition to the lack of full ALTER TABLE support makes alterring a table a very hard task. The built-in sqlite pragmas provide incomplete information and a manual parsing is required in order to extract all the metadata from a table.

```c

PRAGMA table_info(table-name);  

PRAGMA foreign_key_list(table-name);

```

CREATE TABLE syntax diagrams can be found on the official [sqlite website](https://www.sqlite.org/lang_createtable.html).



## Pre-requisites

- A C99 compiler.

- SQL statement must be successfully compiled by SQLite.



## Usage

In order to extract the original CREATE TABLE sql statement you need to query the sqlite_master table from within an SQLite database:

```sql

SELECT sql FROM sqlite_master WHERE name = 'myTable';

```



then just include sql3parse_table.h and sql3parse_table.c in your project and invoke:

```c

// sql is the CREATE TABLE sql statement

// length is the length of sql (if 0 then strlen will be used)

// error is the returned error code (can be NULL)

// return value: NULL in case of error or an opaque pointer in case of success



sql3table *sql3parse_table (const char *sql, size_t length, sql3error_code *error);

```

**sql3table** is an opaque struct that you can introspect using the sql3table* public functions.



## API

```c

// Main Entrypoint

sql3table *sql3parse_table (const char *sql, size_t length, sql3error_code *error);



// Table information

sql3string          *sql3table_schema (sql3table *table);

sql3string          *sql3table_name (sql3table *table);

sql3string          *sql3table_comment (sql3table *table);

bool                sql3table_is_temporary (sql3table *table);

bool                sql3table_is_ifnotexists (sql3table *table);

bool                sql3table_is_withoutrowid (sql3table *table);

size_t              sql3table_num_columns (sql3table *table);

sql3column          *sql3table_get_column (sql3table *table, size_t index);

size_t              sql3table_num_constraints (sql3table *table);

sql3tableconstraint *sql3table_get_constraint (sql3table *table, size_t index);

void                sql3table_free (sql3table *table);

sql3statement_type  sql3table_type (sql3table *table);

sql3string          *sql3table_current_name (sql3table *table);

sql3string          *sql3table_new_name (sql3table *table);



	

// Table constraints

sql3string          *sql3table_constraint_name (sql3tableconstraint *tconstraint);

sql3constraint_type sql3table_constraint_type (sql3tableconstraint *tconstraint);

size_t              sql3table_constraint_num_idxcolumns (sql3tableconstraint *tconstraint);

sql3idxcolumn       *sql3table_constraint_get_idxcolumn (sql3tableconstraint *tconstraint, size_t index);

sql3conflict_clause sql3table_constraint_conflict_clause (sql3tableconstraint *tconstraint);

sql3string          *sql3table_constraint_check_expr (sql3tableconstraint *tconstraint);

size_t              sql3table_constraint_num_fkcolumns (sql3tableconstraint *tconstraint);

sql3string          *sql3table_constraint_get_fkcolumn (sql3tableconstraint *tconstraint, size_t index);

sql3foreignkey      *sql3table_constraint_foreignkey_clause (sql3tableconstraint *tconstraint);



// Column constraints

sql3string          *sql3column_name (sql3column *column);

sql3string          *sql3column_type (sql3column *column);

sql3string          *sql3column_length (sql3column *column);

sql3string          *sql3column_constraint_name (sql3column *column);

sql3string          *sql3column_comment (sql3column *column);

bool                sql3column_is_primarykey (sql3column *column);

bool                sql3column_is_autoincrement (sql3column *column);

bool                sql3column_is_notnull (sql3column *column);

bool                sql3column_is_unique (sql3column *column);

sql3order_clause    sql3column_pk_order (sql3column *column);

sql3conflict_clause sql3column_pk_conflictclause (sql3column *column);

sql3conflict_clause sql3column_notnull_conflictclause (sql3column *column);

sql3conflict_clause sql3column_unique_conflictclause (sql3column *column);

sql3string          *sql3column_check_expr (sql3column *column);

sql3string          *sql3column_default_expr (sql3column *column);

sql3string          *sql3column_collate_name (sql3column *column);

sql3foreignkey      *sql3column_foreignkey_clause (sql3column *column);

	

// Foreign key

sql3string          *sql3foreignkey_table (sql3foreignkey *fk);

size_t              sql3foreignkey_num_columns (sql3foreignkey *fk);

sql3string          *sql3foreignkey_get_column (sql3foreignkey *fk, size_t index);

sql3fk_action       sql3foreignkey_ondelete_action (sql3foreignkey *fk);

sql3fk_action       sql3foreignkey_onupdate_action (sql3foreignkey *fk);

sql3string          *sql3foreignkey_match (sql3foreignkey *fk);

sql3fk_deftype      sql3foreignkey_deferrable (sql3foreignkey *fk);



// Indexed column

sql3string          *sql3idxcolumn_name (sql3idxcolumn *idxcolumn);

sql3string          *sql3idxcolumn_collate (sql3idxcolumn *idxcolumn);

sql3order_clause    sql3idxcolumn_order (sql3idxcolumn *idxcolumn);

	

// String Utils

const char          *sql3string_ptr (sql3string *s, size_t *length);

const char          *sql3string_cstring (sql3string *s);

```



## Example

Dump to stdout complete table information:

```c

// all the necessary code is in sql3parse_debug.h/.c

void table_dump (sql3table *table) {

    if (!table) return;

    

    // schema name

    sql3string *ptr = sql3table_schema(table);

    sql3string_dump(ptr, "Schema Name");

    

    // table name

    ptr = sql3table_name(table);

    sql3string_dump(ptr, "Table Name");



    // table comment

    ptr = sql3table_comment(table);

    if (ptr) sql3string_dump(ptr, "Table Comment");

    

    // table flags

    printf("Temporary: %d\n", sql3table_is_temporary(table));

    printf("If Not Exists: %d\n", sql3table_is_ifnotexists(table));

    printf("Without RowID: %d\n", sql3table_is_withoutrowid(table));

    

    // loop to print complete columns info

    size_t num_columns = sql3table_num_columns(table);

    printf("Num Columns: %zu\n", num_columns);

    for (size_t i=0; i